Add support for KojiResolver in component reuse code.
In this commit, when component reuse code finds out that the base module uses
KojiResolver, it uses the `KojiResolver.get_buildrequired_modules` method
to find out possible modules to reuse and limits the original query just
by the IDs of these modules.
In order to do that, this commit splits the original
`KojiResolver.get_buildrequired_modulemds` into two methods:
- The `get_buildrequired_modules` returning the ModuleBuilds.
- The `get_buildrequired_modulemds` calling the `get_buildrequired_modules`
and returning modulemd metadata.