Set Tephra TTL based on HBase TTL

Ensure that transactional Phoenix tables are setup correctly when they define a TTL (since Tephra has it's own TTL property).

• For a new Phoenix table that is being created, if a TTL property is specified, we should set the TxConstants.PROPERTY_TTL instead of the regular HBase TTL.
• For an existing Phoenix table that is being altered to become transactional, we should leave any existing TTL in place but also add the TxConstants.PROPERTY_TTL with an equivalent value.