feat(repair_test): refactor repair tests (#4266)

* feat(restore_test): improve vnode/tablet keyspace creation

This commit improves keyspace creation functions
so that it's possible to:
- always create vnode keyspace (createVnodeKeyspace)
- create tablet keyspace or skip the test if not possible (createTabletKeyspace)
- create keyspace with default replication type (createDefaultKeyspace)

This makes it possible to:
- run tests against mixed replication type keyspaces
- easily skip the test when it works only with tablets

* refactor(restore_test): separate req/resp parsing and interceptors from the test code

This change allows us to treat repair req/resp
as a black box that is parsed by the test helper methods.
This will make things easier when we introduce new tablet
repair API, which will require parsing different endpoints.

* refactor(restore_test): don't relay on multiple tablet repair requests

With the approaching new tablet repair API, we
won't be able to ensure that tablet table will be repaired
with multiple repair requests. That's why we shouldn't
rely on it by creating tablet keyspaces with a big
number of initial tablets.

Author: Michal-Leszczynski