SOLR-8362: proposal for polyField docValues support for TextField

[magibney]

See: SOLR-8362 Cotinuation of: https://github.com/apache/lucene-solr/pull/1691

This PR introduces docValues support for TextField, supporting

1. sort use case (including configurable post-analysis sort -- a drop-in replacement for SortableTextField, but with more flexibility)
2. facet/significant-terms use case
3. useDocValuesAsStored/valueSource/function/streamingExpression use case (configurable to support arbitrarily large size limits)

The rationale behind this PR is essentially the same as laid out in this comment. The main difference in this PR (as opposed to https://github.com/apache/lucene-solr/pull/1691 described in that comment) is that this PR abandons the hope for Lucene-native support for post-analysis docValues (see LUCENE-10023) and instead generates post-analysis docValues by "pre-analyzing" (at the cost of duplicate effort) in TextField.createFields(...).

Lots of relevant context can also be found at: SOLR-11917.

[magibney]

note: precommit will fail due to nocommits, but existing and new tests all should pass.

[magibney]

For anyone curious about this PR at a high level, the refguide additions might be a good place to start: https://github.com/apache/solr/pull/321/files#diff-c3bd51eeb7d80321dcfd4b8ee946a4c5f17fc22b563fb57dd727baae7461ed46

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