Add initial version of the workflows manager

The workflows manager can be accessed from the extension options, and
will let the user add custom workflows, edit and view the already
created ones, and delete them.

As of now, the only feature implemented is a functional prototype of the
"new workflow" dialog, which is missing the workflow title field and the
functionality to persist the designed workflows. The only action
supported in the workflows editor is the "reply with canned response"

Bug: twpowertools:74
Change-Id: I0d93bf0fdcda92a449855c1f8470f8b7068839aa
diff --git a/package.json b/package.json
index 4c90fd3..8eaa3db 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
   "private": true,
   "dependencies": {
+    "@material/mwc-dialog": "^0.27.0",
     "@material/tooltip": "^12.0.0",
     "@material/web": "^0.1.0-alpha.0",
     "async-mutex": "^0.3.2",