Add `BEFORE_FILE_ADD` and `BEFORE_FILE_DELETE` events

[mehalter]

Did you check the docs?

• [X] I have read all the docs.

Is your feature request related to a problem? Please describe.

The events BEFORE_FILE_MOVE and BEFORE_FILE_RENAME allow us to add support for LSP file operation notifications and queries automatically when performing file moving and renaming. There are actually similar file operations in the LSP spec for file creation and deletion which require events to be triggered before the files are added or deleted. This is currently not possible since neo-tree doesn't emit these events.

Describe the solution you'd like.

Add BEFORE_FILE_ADD and BEFORE_FILE_DELETE events similar to the currently existing BEFORE_FILE_RENAME and BEFORE_FILE_MOVE events to allow the user to add support for the rest of the LSP file operation specification.

Describe alternatives you've considered.

No response

Additional Context

No response

[Woit]

Any updates?