This ticket covers the work for making the ChunkManager support routing at different timestamps. Essentially, implementing the CatalogCache::getCollectionRoutingInfoAt interface.

As part of this work, in addition to the existing ChunkManager unit-test coverage, we should add new tests which construct routing information at different points in time and ask for:

• The latest Timestamp (no Timestamp should be covered by the existing coverage)
• Timestamps at Timestamp boundaries (making sure we don't have boundary condition bugs)
• Timestamps, which are before the earliest supported, ensuring that TimestampTooOld exception is thrown