dovecot: replace solr fts with flatcurve (xapian) (#5680)

* fts-flatcurve: inital implementation

* fts: removed solr from compose.yml

* flatcurve: added heap and proc logic to dovecot

* added logic for update.sh & generate for Flatcurve

* delete old iteration of fts-flatcurve.conf

* updated default fts.conf

* updated .gitignore to exclude fts.conf for further git updates

* Remove autogeneration of fts.conf (disable override)

* cleanup all left solr stuff

* renamed SKIP_FLATCURVE to SKIP_FTS

* cleanup leftovers solr in lang files

* moved lazy_expunge plugin only to mail_plugins

* added fts timeout value

* compose: remove dev image of dovecot

* updated japanese translation

data/web/lang/lang.si-si.json

@@ -501,12 +501,9 @@
         "last_modified": "Nazadnje spremenjeno",
         "history_all_servers": "Zgodovina (vsi strežniki)",
         "in_memory_logs": "In-memory dnevniki",
-        "jvm_memory_solr": "JVM zasedenost spomina",
         "service": "Servis",
         "show_ip": "Prikaži javni IP",
         "size": "Velikost",
-        "solr_dead": "Solr se zaganja, je onemogočen ali se je ustavil.",
-        "solr_status": "Status Solr",
         "started_at": "Zagnano ob",
         "started_on": "Zagnano na",
         "static_logs": "Statični dnevniki",