For popular modules used by many DevTools add-ons, add shim files which wrap the
modules and make them available at their previous location.
Each shim includes a deprecation warning to make devs and users aware of the
issue.
--HG--
rename : devtools/server/dbg-server.jsm => devtools/server/shims/dbg-server.jsm
rename : devtools/shared/client/dbg-client.jsm => devtools/shared/shims/dbg-client.jsm
extra : commitid : H7Y9k2ADf0u
extra : rebase_source : 2bd193ecd4f2baeb8b14c14c63884d3a318a0840