TechDocs: Use a flag to determine if we should use a local mkdocs or techdocs-container (#2503)

* Use a flag to determine wether to use techdocs-container or local install of mkdocs

* Updated techdocs generator to look at app-config string instead of argument to decide how to run the generator

* Removed console log...

* Reverted scaffolder file that was accidentally committed.

* Fixed lint issues

* Added config to create-app template

app-config.yaml

@@ -35,6 +35,8 @@ organization:
 techdocs:
   storageUrl: http://localhost:7000/techdocs/static/docs
   requestUrl: http://localhost:7000/techdocs/docs
+  generators:
+    techdocs: 'docker'
 
 sentry:
   organization: spotify