Feature / user recommendation config in admin ui (#3357)

* add config for external user recommendation into admin ui

* debug

* correct admin ui

* switch external user recommendation to admin ui config

* debug

* debug

* debug

* Revert "debug"

This reverts commit f4a0460e5b.

* explicit parseInt radix

* add Japanese message

* change default engine to https

* remove unused settings

* debug

* nullable externalUserRecommendationTimeout

.config/example.yml

@@ -121,9 +121,3 @@ autoAdmin: true
 
 # Summaly proxy
 #summalyProxy: "http://example.com"
-
-# User recommendation
-#user_recommendation:
-#  external: true
-#  engine: http://vinayaka.distsn.org/cgi-bin/vinayaka-user-match-misskey-api.cgi?{{host}}+{{user}}+{{limit}}+{{offset}}
-#  timeout: 300000