Add ALERename (tsserver & LSP), ALEOrganizeImports (tsserver) and auto import support (tsserver) (#2709)

This commit adds support for renaming symbols in tsserver and with LSP tools, and for organising imports with tsserver. Completion results for symbols that can be imported are now suggested if enabled for tsserver completion done via ALE.

test/test_autocmd_commands.vader

@@ -188,6 +188,10 @@ Execute (ALECleanupGroup should include the right commands):
     \], CheckAutocmd('ALECleanupGroup')
   endif
 
+Execute(ALECompletionActions should always be set up):
+  AssertEqual [
+  \ 'CompleteDone * call ale#completion#HandleUserData(v:completed_item)',
+  \], CheckAutocmd('ALECompletionActions')
 
 Execute(Enabling completion should set up autocmd events correctly):
   let g:ale_completion_enabled = 0