This commit removes all support in the compiler for the #[crate_id] attribute
and all of its derivative infrastructure. A list of the functionality removed is:

* The #[crate_id] attribute no longer exists
* There is no longer the concept of a version of a crate
* Version numbers are no longer appended to symbol names
* The --crate-id command line option has been removed

To migrate forward, rename #[crate_id] to #[crate_name] and only the name of the
crate itself should be mentioned. The version/path of the old crate id should be
removed.

For a transitionary state, the #[crate_id] attribute is still accepted if
the #[crate_name] is not present, but it is warned about if it is the only
identifier present.

RFC: 0035-remove-crate-id
[breaking-change]