Feat: Create Merge Request (#149)

- Adds the ability to create MRs to the plugin
- Adds the ability to jump to specific discussions/notes in the browser
- Fixes stale icons
- Adds debug keybinding for discussion tree for developers

lua/gitlab/actions/discussions/annotations.lua

@@ -49,6 +49,7 @@
 ---@field resolved_by Author
 ---@field resolved_at string?
 ---@field noteable_iid integer
+---@field url string?
 
 ---@class UnlinkedNote: Note
 ---@field position nil