cadc-11115 new caom2-meta-sync module

[jburke-cadc]

No description provided.

[pdowler]

Haven't looked at Main yet; config/doc changes first and that will reduce what's in Main

[pdowler]

README and configuration:

Until we get a response from Job on the db, let's simplify as much as possible:

1. get rid of dryrun - it's useless
2. change runContinuously to exitWhenComplete, make it optional, and default to false: that way run forever is the normal mode and this is an exception for special cases
3. both threads and batchSize are implementation details that we unfortunately expose to operators and explaining sensible values will be very hard... let's make those internal and for now hard code to batchSize=100 and nthreads=batchSize/10.
4. change maxSleep to maxIdle and keep it with the "source" config items
5. hide (remove?) the "source db" config documentation for now
6. use org.opencadc.caom2.metasync.repoService for source config, move the org.opencadc.caom2.metasync.collection up beside the repoService and make it clear that multiple values are allowed; put all "source:" config before "destination" config
7. use org.opencadc.caom2.metasync.db.* for destination config; keep org.opencadc.caom2.metasync.basePublisherID with destination config

Style: In the text that explains each config property, you don't need to write out the whole property. It's hard to read... see fenwick (trackSiteLocations) or tantar (buckets) for two styles that seem to be sufficient ref to the config spec and more readable (just inconsistent, but I think I prefer the italics since they aren't literally exact).