Add more git commands

Version information

Thunar 4.18.4 Linux Mint 22 https://docs.xfce.org/xfce/thunar/thunar-vcs-plugin

Creating this issue following https://gitlab.xfce.org/xfce/thunar/-/work_items/1745. I created a lot of Custom Actions on Thunar for Git, you can see some of the Custom Actions I created here: https://gitlab.xfce.org/-/project/8/uploads/449526bc405e1ccb5f5ae96cf2f48446/Custom_Actions_window.png

The problems with thunar-vcs-plugin are:

• that it misses a lot of options;
• that it should only show it's options inside folders/files that are inside a folder that contains a ".git" folder (in case of Git repositories, in case of SVN repositories I don't know), except maybe the "git init" option that should be shown on all the folders that aren't inside a folder that contains a ".git" folder. Check issue #12.

Check some of the Custom Actions for Git I created here: https://gitlab.xfce.org/-/project/8/uploads/9ca5835d56f60ac78786bc0be4fb6edc/uca.xml

Thanks.