Target SiriIntents: Split IntentHandler into smaller files (#6203)

* Add protocol `ContactResolving`

* Let the `IntentHandler` implement `ContactResolving` (#6203)

Nothing has changed about the implementation itself; this prepares
the separation of this logic into a dedicated unit.

* Prepare the separation of the contact resolver from the intents handler (#6203)

* Move the implementation of `ContactResolving` to a dedicated class (#6203)

* Move `ContactResolver` to a dedicated file (#6203)

* Prepare the separation of the `StartAudioCallIntentHandler` from `IntentsHandler` (#6203)

* Move the implementation of `INStartAudioCallIntentHandling` to a dedicated class (#6203)

* Prepare the separation of the `StartVideoCallIntentHandler` from `IntentsHandler` (#6203)

* Move the implementation of `INStartVideoCallIntentHandling` to a dedicated class (#6203)

* Prepare the separation of the `SendMessageIntentHandler` from `IntentsHandler` (#6203)

* Move the implementation of `INSendMessageIntentHandling` to a dedicated class (#6203)

* Remove unused property (#6203)

* Return `nil` if the requested intent cannot be handled (#6203)

* Initialize the intent handlers _after_ everything else is configured (#6203)

In `init()`, there might be some configuration being done that is
required for the handlers.

* Add changelog entry

* Move curly braces in Objective-C to dedicated lines

This ensures that the code follows the style that is present in other Objective-C files.

Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>

* Inject the `ContactResolver` into the intent handlers during initialization

In #6365, @pixlwave pointed out that

> If the resolver ever gained a cache or stored properties it would
> help keep the memory usage down in the extension

* Prefer forward-declaration over import in Objective-C header files

Per @pixlwave, this helps prevent build failures:

> We had random cycle errors while building a while back and it was
> eventually solved by removing all imports of `GeneratedInterface-Swift.h`
> in every [Objective-C header] file.

Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>

SiriIntents/IntentHandlers/StartAudioCall/StartAudioCallIntentHandler.m

@@ -0,0 +1,90 @@
+// 
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#import "StartAudioCallIntentHandler.h"
+#import "MXKAccountManager.h"
+#import "ContactResolver.h"
+#import "GeneratedInterface-Swift.h"
+
+@interface StartAudioCallIntentHandler ()
+
+@property (nonatomic) id<ContactResolving> contactResolver;
+
+@end
+
+@implementation StartAudioCallIntentHandler
+
+- (instancetype)initWithContactResolver:(id<ContactResolving>)contactResolver
+{
+    if (self = [super init]) {
+        _contactResolver = contactResolver;
+    }
+    
+    return self;
+}
+
+#pragma mark - INStartAudioCallIntentHandling
+
+- (void)resolveContactsForStartAudioCall:(INStartAudioCallIntent *)intent withCompletion:(void (^)(NSArray<INPersonResolutionResult *> * _Nonnull))completion
+{
+    [self.contactResolver resolveContacts:intent.contacts withCompletion:completion];
+}
+
+- (void)confirmStartAudioCall:(INStartAudioCallIntent *)intent completion:(void (^)(INStartAudioCallIntentResponse * _Nonnull))completion
+{
+    INStartAudioCallIntentResponse *response = nil;
+    
+    MXKAccount *account = [MXKAccountManager sharedManager].activeAccounts.firstObject;
+    if (account)
+    {
+#if defined MX_CALL_STACK_OPENWEBRTC || defined MX_CALL_STACK_ENDPOINT || defined CALL_STACK_JINGLE
+        NSUserActivity *userActivity = [[NSUserActivity alloc] initWithActivityType:NSStringFromClass([INStartAudioCallIntent class])];
+        response = [[INStartAudioCallIntentResponse alloc] initWithCode:INStartAudioCallIntentResponseCodeReady userActivity:userActivity];
+#else
+        response = [[INStartAudioCallIntentResponse alloc] initWithCode:INStartAudioCallIntentResponseCodeFailureCallingServiceNotAvailable userActivity:nil];
+#endif
+    }
+    else
+    {
+        // User hasn't logged in
+        response = [[INStartAudioCallIntentResponse alloc] initWithCode:INStartAudioCallIntentResponseCodeFailureAppConfigurationRequired userActivity:nil];
+    }
+    
+    completion(response);
+}
+
+- (void)handleStartAudioCall:(INStartAudioCallIntent *)intent completion:(void (^)(INStartAudioCallIntentResponse * _Nonnull))completion
+{
+    INStartAudioCallIntentResponse *response = nil;
+    
+    INPerson *person = intent.contacts.firstObject;
+    if (person && person.customIdentifier)
+    {
+        NSUserActivity *userActivity = [[NSUserActivity alloc] initWithActivityType:NSStringFromClass(INStartAudioCallIntent.class)];
+        userActivity.userInfo = @{ @"roomID" : person.customIdentifier };
+        
+        response = [[INStartAudioCallIntentResponse alloc] initWithCode:INStartAudioCallIntentResponseCodeContinueInApp
+                                                           userActivity:userActivity];
+    }
+    else
+    {
+        response = [[INStartAudioCallIntentResponse alloc] initWithCode:INStartAudioCallIntentResponseCodeFailure userActivity:nil];
+    }
+
+    completion(response);
+}
+
+@end