New documentation graphics

[jbampton]

First up we need new graphics for the top of these pages:

https://slurp.readthedocs.io/en/latest/database.html https://slurp.readthedocs.io/en/latest/sql-file.html https://slurp.readthedocs.io/en/latest/git.html https://slurp.readthedocs.io/en/latest/pylint.html