Create background and avatar generator

[mastercyb]

• definition of a deterministic pattern generation method
• api defenition
• choosing an art style
• drawing assets
• implementation
• performance optimizations

[mastercyb]

I will start to gather arts for motivation:

[mastercyb]

[mastercyb]

Existing pattern generators:

• https://github.com/jasonlong/geo_pattern - quite primitive
• http://btmills.github.io/geopattern/ - good example of how this must work
• https://github.com/e1ven/Robohash - the thing we already use
• https://github.com/monteslu/robojs - very compact lib