[DOCS] Move anomaly detection job resource definitions into APIs

[lcawl]

This PR adds tagged sections that contain descriptions of the anomaly detection job resource properties in https://github.com/elastic/elasticsearch/blob/master/docs/reference/ml/ml-shared.asciidoc. It removes the job resource definitions page (https://www.elastic.co/guide/en/elasticsearch/reference/master/ml-job-resource.html) and uses the shared tagged sections to put that information directly into the appropriate APIs.

NOTE: As a result of these changes, users no longer need to flip between the job resource page and the API page to find all the necessary details. However, from a maintenance stand-point, it means that when parameters or properties are added or removed, each of the affected APIs' pages must be updated appropriately.

Subsequent PRs will be opened to (1) add missing indicators of which properties are required or optional in the create job API, (2) minimize some of the overly long property descriptions, and (3) merge some of the varied definitions for "job_id", since it seems unlikely so many variations are needed.

Preview:
http://elasticsearch_49700.docs-preview.app.elstc.co/guide/en/elasticsearch/reference/master/ml-put-job.html
http://elasticsearch_49700.docs-preview.app.elstc.co/guide/en/elasticsearch/reference/master/ml-get-job.html
http://elasticsearch_49700.docs-preview.app.elstc.co/guide/en/elasticsearch/reference/master/ml-update-job.html
...

[elasticmachine]

Pinging @elastic/ml-core (:ml)

[edsavage]

Looks like the CI build failed due to...

WARNING: ml/anomaly-detection/apis/put-job.asciidoc: line 36: tag 'job-id-def' not found in include file: /tmp/docsbuild/cyKWLdPar0/elasticsearch/docs/reference/rest-api/common-parms.asciidoc

[edsavage]

CI failed due to

Invalid json in reference/ml/anomaly-detection/apis/get-job.asciidoc154:207// TESTRESPONSE. The error is:
23:18:50 expecting '}' or ',' but got current char '.' with an int value of 46

This is due to some dodgy JSON introduced in commit 9c997cf

[lcawl]

@elasticmachine elasticseach-ci/docs-check

[lcawl]

@elasticmachine run elasticsearch-ci/docs-check

[elasticmachine]

Pinging @elastic/es-docs (>docs)

[szabosteve]

LGTM!
I left a few comments and suggestions, nothing blocker though. Thank you for this enormous work!

[szabosteve]

Suggested change

	(time units)
	(<<time-units,time units>>)

[szabosteve]

I'm wondering if we can put it back until I start to work on the DFA related parameters? I'd like to be consistent, too, but then we need to delete the name and the indicators between parentheses in the cases of dependent_variable, gamma, eta, lambda, feature_bag_fraction, maximum_number_trees, and so on, then open a PR that adds the removed info back to the API docs. Finally, merge and backport the two PRs (this one and the one that put the titles and indicators back to the API docs) in sync.
The other option is to leave it as-is for now and I'll remove the titles in this file and add them back in the API docs in one PR later. WDYT? If my train of thought is obscure and I explained my concern poorly, please let me know.

Suggested change

	Defines which field of the document is to be predicted.
	`dependent_variable`::
	(Required, string) Defines which field of the document is to be predicted.

[lcawl]

Agreed, there was no reason for me to change this, since it isn't used by any of the APIs I updated.