Implement dryrun parameter for PID updates

[Pfeil]

Motivated by #243, as it tests precisely this case. This PR was not able to reproduce the issue!

This implements dryrun for the update API. This means:

• It will require a valid record, including matching PIDs in URL and record (although the record PID can be omitted, as before).
• It will require a valid etag of the previous version
• The PID needs to exist
• The new etag will be returned
• Nothing really changes
  • The PID record will not be modified
  • No AMQP message will be sent
  • No elastic index will be updated, etc

How does it differ from the create-dryrun? Mainly in that it has the properties of an update:

• The PID needs to exist in beforehand (opposite to create)
• Etag is required
• New etag will be returned

Why do we need this?

• Consistency: It seems this is kind of expected by users.
• Testing: It allows to at least partially test the handle protocol with create/update, although it does currently not really increase the test coverage. This may change over time as we plan to package all functionality which does not need authentication into other classes, which then may be executed in tests.

Other noteworthy changes:

• improved logging on update if PIDs do not match, to have a more comprehensible source of information in such error reports
• added an update test using dryrun using the read-only handle protocol tests

Breaking changes:

• none expected

[coveralls]

Pull Request Test Coverage Report for Build #429

Details

• 129 of 138 (93.48%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.07%) to 72.4%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/edu/kit/datamanager/pit/web/impl/TypingRESTResourceImpl.java	129	138	93.48%

Totals
Change from base Build #425:	0.07%
Covered Lines:	884
Relevant Lines:	1221

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💛 - Coveralls