rename `wasi:blobstore/blobstore` to `wasi:blob/store` and other tidy up

[Mossaka]

• rename the wasi:blobstore/blobstore to wasi:blob/store
• add docs to the wasi:blob/imports World
• update the markdown docs file
• moved wasi:blob/container to the inside of wasi:blob/store
• deleted container.wit

@thomastaylor312 @lukewagner

discussion: I would like to document the changes in a CHANGELOG file that follows keep a changelog