Prepare #904: Improve the people invite screens

- Rename `ContactPickerViewController` with `HomePeopleSearchViewController`.
- Define a basic view controller class `ContactsTableViewController` to display/filter a contacts list.
- Make `StartChatViewController` inherit of this new class `ContactsTableViewController` to handle contact invite.

Vector/ViewController/StartChatViewController.h

@@ -14,16 +14,13 @@
  limitations under the License.
  */
 
-#import <MatrixKit/MatrixKit.h>
-
-#import "ContactTableViewCell.h"
+#import "ContactsTableViewController.h"
 
 /**
  'StartChatViewController' instance is used to prepare new room creation.
  */
-@interface StartChatViewController : MXKViewController <UITableViewDelegate, UITableViewDataSource, UISearchBarDelegate>
+@interface StartChatViewController : ContactsTableViewController <UISearchBarDelegate>
 
-@property (weak, nonatomic) IBOutlet UITableView *tableView;
 @property (weak, nonatomic) IBOutlet UIView *searchBarHeader;
 @property (weak, nonatomic) IBOutlet UISearchBar *searchBarView;
 @property (weak, nonatomic) IBOutlet UIView *searchBarHeaderBorder;
@@ -50,7 +47,7 @@
  @discussion This is the designated initializer for programmatic instantiation.
  @return An initialized `StartChatViewController` object if successful, `nil` otherwise.
  */
-+ (instancetype)roomParticipantsViewController;
++ (instancetype)startChatViewController;
 
 @end