Switched over substr and trim functions in str to be non-allocating, temporary renamed them to better track use-sites

renamed str::slice -> slice_DBG_UNIQ
changed vec slice method -> to_owned()
renamed vec view method  -> slice_V_DBG_BRWD

This starts moving a bunch of privacy checks into the privacy
checking phase and out of resolve.

are currently inferred.  New rules are coming that will require
them to be explicit.  All add some explicit self declarations.