Fix MR Selection, Go Code Refactor (#358)

refactor: Refactors the Go codebase into a more modular and idiomatic approach
fix: require selection of specific MR when there are multiple targets for a given source branch
feat: Allows for the passing of Gitlab's filter options when choosing an MR, improves MR selection
feat: API to choose an MR from a list based on the provided username's involvement as an assignee/reviewer/author

This is a #MINOR release

lua/gitlab/init.lua

@@ -26,6 +26,7 @@ local project_members = state.dependencies.project_members
 local latest_pipeline = state.dependencies.latest_pipeline
 local revisions = state.dependencies.revisions
 local merge_requests_dep = state.dependencies.merge_requests
+local merge_requests_by_username_dep = state.dependencies.merge_requests_by_username
 local draft_notes_dep = state.dependencies.draft_notes
 local discussion_data = state.dependencies.discussion_data
 
@@ -102,6 +103,10 @@ return {
   data = data.data,
   print_settings = state.print_settings,
   choose_merge_request = async.sequence({ merge_requests_dep }, merge_requests.choose_merge_request),
+  choose_merge_request_by_username = async.sequence(
+    { project_members, merge_requests_by_username_dep },
+    merge_requests.choose_merge_request
+  ),
   open_in_browser = async.sequence({ info }, function()
     local web_url = u.get_web_url()
     if web_url ~= nil then