* 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.
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