Specify/advise semantics of default Container resources (index.html/.ttl)

A topic that causes a lot of implementor and app-developer confusion is the handling of default resources for Containers - index.html and/or index.ttl.

Questions:

1. Is the index.html behavior a MUST or MAY?
2. Is the index.ttl behavior a MUST or MAY?
3. How to prevent the fairly common occurrence of "I accidentally created an index.html but forgot to add an .acl, plus that kicks me out of the Data browser, so anyways what do I do now."

In either case, we should either add it to spec or provide non-normative text advising devs what to do.

Related issues:

• solid-spec/134 - Make handling of default resource for container explicit
• wac/36 - Make explicit in spec that when a default resource is served for a container, server should check ACL for that resource #36
• solid/213 - How do I delete/move a created resource?
• solid/159 - Blocked editing to Public Folder...