Relation to LWS WG Type Indexes and Access Requests/Grants

[elf-pavlik]

How shapes defined here are goning to work with this ealry work from LWS WG

• add Type Index Section w3c/lws-protocol#115
• Add editors draft for LWS Access Requests and Access Grants w3c/lws-protocol#106

In SAI https://shapetrees.org/ are used as a common reference in Access Requests, Access Grants and equivalent of LWS Type Indexes. Looking at this thread w3c/lws-protocol#106 (comment)

It seems that types are currently conidered as the common reference, which doesn't seem to clearly tie with using shapes defined here.

/cc @jeswr @jaxoncreed