In order to allow for smooth deployment and easier debugging it would be beneficial to be able to control in which scenarios requests against the newly introduced SSR service are performed. This is particularly important as results of the requests for user-specific termbox markup are not cached/hardly cachable.
AC:
* there exists a config variable "termboxUserSpecificSsrEnabled" to `Enable/Disable server-side rendering (SSR) for user-specific termbox markup. The default setting is <code>true</code>. It only comes into effect if the general "termboxEnabled" is <code>true</code>. If disabled, user-specific termbox markup will only be created by client-side rendering after initial diplaying of the generic termbox markup.` See [[ https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/Wikibase/+/master/docs/options.wiki#188 | termboxEnabled ]]