dovecot-fts-solr Solr9 support

[Nathanael Anderson]

I was trying a new install of dovecot w/ solr9.   I've manually fixed 
the file linking to the proper directories, however one plugin is no 
longer shipped.   Since the solr files aren't updated yet to 9, can 
anyone tell me if I need the discontinued velocity plugin that was 
default in the dovecot solr 7.7 config file.   It appears it is now a 
third party plugin that hasn't been updated for 3 years.