ILM: parse origination date from index name (#46755)

[andreidan]

• ILM: parse origination date from index name

Introduce the index.lifecycle.parse_origination_date setting that
indicates if the origination date should be parsed from the index name.
If set to true an index which doesn't match the expected format (namely
indexName-{dateFormat}-optional_digits will fail before being created.
The origination date will be parsed when initialising a lifecycle for an
index and it will be set as the index.lifecycle.origination_date for
that index.

A user set value for index.lifecycle.origination_date will always
override a possible parsable date from the index name.

(cherry picked from commit c363d27)
Signed-off-by: Andrei Dan andrei.dan@elastic.co

Backport of #46755

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[andreidan]

@dakrone I added a commit on this backport as didn't realise 7x still runs on java 8 and a test used Map.of which is not available until java 9

9f854e1

[dakrone]

I added a commit on this backport as didn't realise 7x still runs on java 8 and a test used Map.of which is not available until java 9

No problem, we sometimes have to make minor changes during backports. This should be fine assuming CI is happy.