Add ability to install clickhouse-keeper

[azat]

There is now the same thing for client-only setup - clickhouse_setup=client, what we need is a clickhouse-keeper only installation, with clickhouse_setup=keeper

We already have a role for keeper, but it is private.

But it looks like it should fit this role and no need to creating a separate for this.

Note, that keeper supports YAML configs, so we should use them instead of XML like in our role right now.