Search commits by sha

[khoan]

Is your feature request related to a problem? Please describe.
Unable to view a commit by its sha.

Describe the solution you'd like
Hit s, then enter sha

Describe alternatives you've considered
Using Up/Down, PageUp/PageDown is cumbersome.

Additional context
Nice work! Thanks.

[extrawurst]

@khoan thanks for your interest in gitui. this feature is on my list of long term goals aswell!