Add two collations for Russian language: utf8mb4_ru_0900_ai_ci and
utf8mb4_ru_0900_as_cs.

CLDR defines only a very simply reorder rule for Russian language. We
have implemented 'reorder' in WL#9108, so there is no special work
needed for these two collations.

CLDR defines a few weight tailoring rules for Cyrillic characters in
its root collation. But these rules are for 'eor' collation type, which
these two collations will not fall back to, because these collations
are of 'standard' collation type. So we don't use these rules.

Change-Id: If1a33eb8ece34e6bdc1362f803ff7a347efd50a9