INT-3359: Add `GemfireLockRegistry`

JIRA: https://jira.spring.io/browse/INT-3359
INT-3355 Redis Tests Minor Polishing

JIRA: https://jira.spring.io/browse/INT-3355

Minor issues/typos noticed while back porting.
INT-3339: Add `priority` to the `JdbcChannelMS`

JIRA: https://jira.spring.io/browse/INT-3339
INT-3339: Improve `priority` logic
INT-3339: Add `MESSAGE_SEQUENCE` stuff
INT-3339: Docs