[Feature]: properly sync the plugins on git changes

[kylo252]

Feature motivation

We should have a robust way that detects changes or conflicts that could lead to Packer errors. Such changes can include:

• list of core plugins being out-of-sync [added/removed entries]
• list of user plugins being out-of-sync [added/removed entries]
• missing $LUNARVIM_CONFIG_DIR/plugins/packer_compiled.lua
• corrupted $LUNARVIM_CONFIG_DIR/plugins/packer_compiled.lua [unlikely]

Describe the expected solution

1. Check if the content of the core/user plugins list has changed

2. Perform a clean-up for Packer environment:

   # semi psuedo-code
   if [ -e $LUNARVIM_CONFIG_DIR/plugins/packer_compiled.lua ]; then
         rm -rf $LUNARVIM_CONFIG_DIR/plugins/packer_compiled.lua
   fi
   # TODO: make sure the timeout is enough
   lvim --headless +'autocmd User PackerComplete sleep 100m | qall' +PackerSync
   # TODO: find a way for error handling
   lvim --headless +'autocmd User PackerComplete sleep 100m | qall' +PackerCompile

Describe the alternatives you've considered

It might be possible to do with a git hook using https://github.com/facebook/watchman

Example:

https://github.com/git/git/blob/225bc32a989d7a22fa6addafd4ce7dcd04675dbf/templates/hooks--fsmonitor-watchman.sample#L1-L10

Additional context

No response

[abzcoding]

#1399

[ahmedkhalf]

I would like to suggest that if #1397 get's implemented then step 2 could easily be implemented in a cross-platform way. (see lvim clean)