Support file indexing and searching

[ypid]

I have not looked into this but Nextant sounds promising.

[drybjed]

Apparently it uses solr which is available in Debian. It's Java, but if it's an optional resource, I suppose that we can go with that.

[ypid]

Seems this is now handled by Elasticsearch directly which I know quite well by now and for which we have a role 😉

Ref: https://github.com/nextcloud/fulltextsearch/wiki/Basic-Installation