Add terms.list parameter to the TermsComponent to fetch the docFreq for a list of terms

This ticket will add a terms.list parameter to the TermsComponent to retrieve Terms and docFreq for a specific list of Terms.

This is needed to support SOLR-9193 which needs to fetch the docFreq for a list of Terms.

This should also be useful as a general tool for fetching docFreq given a list of Terms.