Add icons for git item

[johnr14]

Add the possibility to enable and disable git icons for repository status.

Description

Wanted icons for gits that can be changed with variables.

• add space before icon so they are not small
• fix icon enabling and disabling with appropriate spacing if needed
• will change style on tide configure re-run

Icons can be changed by changing following variables :

tide_git_icon
tide_git_icon_conflicted
tide_git_icon_dirty 
tide_git_icon_spacer
tide_git_icon_staged 
tide_git_icon_stash 
tide_git_icon_untracked 
tide_git_icon_upstream_ahead
tide_git_icon_upstream_behind

Motivation and Context

This is to enable replacing * ~ + ! ? with nerd fonts symbols 󱉰    󰩌 Note: Open to other symbols !

Closes #349 Edit: Closes #239

Screenshots (if appropriate)

Edit: no remote defined or github.com icon if remote is set to git@github.com

How Has This Been Tested

• [x] I have tested using Linux.
• [ ] I have tested using MacOS.

Checklist

• [ ] I am ready to update the wiki accordingly.
• [ ] I have updated the tests accordingly.

[johnr14]

Edit: To pass tests, original code is used when tide_git_icon_true is not set.

Thanks

[johnr14]

Added icon for github.com remote. Closes #239