* ingest: Introduce the dissect processor
The ingest node dissect processor is an alternative to Grok
to split a string based on a pattern. Dissect differs from
Grok such that regular expressions are not used to split the
string.
Dissect can be used to parse a source text field with a
simpler pattern, and is often faster the Grok for basic string
parsing. This processor uses the dissect library which
does most of the work.
* INGEST: Make a few Processors callable by Painless
* Extracted a few stateless String processors as well as the json processor to static methods and whitelisted them in Painless
* provide whitelist from processors plugin
Folded grok processor into ingest-common module.
The rest tests have been moved to ingest-common module as well, because these tests don't run in the rest-api-spec module but in the distribution:integ-test-zip module
and adding a test plugin there felt just wrong to me. I think this is ok. I left a tiny ingest rest test behind in that tests with an empty pipeline.
Removed messy tests, these tests were already covered in the rest tests
Added ingest test plugin in test infra so that each module testing integration with ingest doesn't need write its own plugin
Moved reindex ingest tests to qa module
Closes#18490