Red Aluminium Spitz

Adds an In-Memory Filesystem adapter. This means images wont be saved to the disk (in .cache) and instead will be saved by a proxy cache or http accelerator like Varnish.

Changes/Additions:

• New Config Section d797b24
• Getters and Setters 65c1223
• Composer json update e6ed136
• Flysystem Adapter 0f49a8e
• Added to backend docs 6d93cf8