Copy normalisers for keyword fields to rollup indexes

[colings86]

At the moment rollups do not copy normalisers for keyword fields over to the rollup index. This means that will the introduction of #30973 enabling the match query to be used against rollup indexes the match query will work differently on live indexes to rollup indexes. The difference will be that a match query against a keyword field in a live index will get a configured normaliser applied to the query text and will match documents, but running the same query against a rollup index will potentially not match documents because the normaliser will not be applied to the query text.

For example:
If I have a field that has a lowercasing normaliser on the live index and do a rollup search across live and rollup indexes for mySQL, it will find documents in the live index and return them but it will look like there are no matching documents in the rollup index because the same normalisation was not applied on the rollup index.

We should make a change to the index side of rollups to copy over any normalisers that are configure on keyword fields we are using in the rollups.

[elasticmachine]

Pinging @elastic/es-search-aggs

[jimczi]

We've decided to not allow match queries in rollup at the moment. text fields are not handled in rollups so the need for this type of query is still unclear. We still need to handle normalizer in rollups for keyword field since the term query uses them, I removed the blocker label but we should at least document the limitation.