Allow custom server ID for publishing Java artifacts.

[tweise]

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---	---	---	---	---
Java
Python		---		---	---	---	---

[pabloem]

If I understand correctly, you can pass -PdistMgmtServerId=... and publish to your particular artifactory? If that's the case, then this LGTM

Also, I saw that you wanted to skip signing? perhaps we could add a -PnoSign flag, or allow the publish task to exist without -PisRelease.

[tweise]

@pabloem this is how I would run the command:
./gradlew :beam-runners-flink_2.11-job-server:publish -Ppublishing -PdistMgmtSnapshotsUrl=https://mycustomrepo/libs-snapshots -PdistMgmtServerId=snapshots --no-parallel --no-daemon

Looking at adding the -PnoSign flag now..

[tweise]

@lukecwik @pabloem PTAL

[pabloem]

LGTM!