Add exec to rebase interactive

[OJarrisonn]

Is your feature request related to a problem? Please describe.
Sometimes i need to do a change in some past commit (or in several commits) during an interactive rebase With git rebase --interactive i have the oportunity to insert some exec commands between picks, squashes, etc. so those changes are applied

Describe the solution you'd like
Being able to add press a key, say x and insert a command and exec it on the selected commits similar to the interactive git rebase

Describe alternatives you've considered
Maybe this feature could be implemented as a custom shortcut, but i don't have enough knowledge about lazygit shortcuts customization to try it myself