New Octocats and Logo

[Lucaffo]

Also, old logo and octocats need to be refactored into a common size ( With exception )
2000x2000 can be a valid default format

[Lucaffo]

https://myoctocat.com/
https://octodex.github.com/

[Lucaffo]

Auto fetch from octodex? by name?
https://octodex.github.com/images/securityknightocat.png

seems
https://octodex.github.com//images/.png