DOC: Move all docs into en/ subdirectory (#1505)

* DOC: Move all docs into en/ subdirectory

PR #1502 is working on adding a Chinese translation to the docs. In
general, I encouraged this (in #1452) as a path towards getting useful
translated content in the game without requiring a massive
refactor/rearchitecting of everything.

To support this, this takes the first step of moving our docs into an
en/ subdirectory, so that other languages can live alongside. No effort
is made at this time to support or select between alternate languages;
this is a pure-rename refactor.

src/Documentation/doc/en/basic/hacknet_nodes.md

@@ -0,0 +1,9 @@
+# Hacknet nodes
+
+This distributed network of computers allows you to gain passive income.
+By upgrading a node's level, RAM, and CPU cores you can increase the amount of money it earns.
+You can also purchase new nodes to expand your Hacknet - The cost for each node increases as your network grows.
+
+**Hacknet nodes won't make as much money as basic hacking scripts, and they are not enough to progress alone.**
+
+Later in the game, there is a powerful change to the Hacknet system called [Hacknet Servers](../advanced/hacknetservers.md).