Issue-768 Support Markdown Emoji

[andrewpollack]

Please let me know any ways that this PR can be improved! It's my first time contributing to a Rust project, so hopefully this all makes sense!

This Pull Request fixes/closes #768 .

It changes the following:

• Adds ''gh-emoji" crate to dependencies
• Added emoji functionality to 'commitlist.rs' commit msg

I followed the checklist:

• I added unittests
• I ran make check without errors
• I tested the overall application
• I added an appropriate item to the changelog

[extrawurst]

Hi @andrewpollack thanks for tackling this!

Please check out my comment in the issue:

Note: In case anyone wants to tackle this - make sure to not run the parser on every draw but just on the cache of commits we keep in memory

Please use LogEntry::from to parse for emojis and write a unittest and a changelog entry.

[andrewpollack]

@extrawurst Ahh that makes perfect sense! I'll close this PR for now, and reopen once these changes are made