This reverts commit 7e844adde2.
Keep NERDTree instead of nvim tree lua.
Mostly because it uses very small inputs for file paths.
I couldn't find an easy way to move files.
It opens files with absolute path instead of relative to cwd which will
also influence my snippets.
I managed my setup manually.
This commit ports the existing setup to home-manager.
The program module is used to install neovim together with plugins.
Custom plugins are now maintained at Gitea / GitHub and loaded via nix as well.