remove: remove C APIs in favor of random/base/shared

With the creation of `@stdlib/random/base/shared`, the C APIs in
the sub-namespace are now redundant and can be removed.

BREAKING CHANGE: deprecate C APIs in favor of `random/base/shared`

To migrate, users should explicitly depend on `@stdlib/random/base/shared`
and update their include paths accordingly.

Ref: #1342
Ref: #1199

Author: kgryte