Revert "cui: add entry "RestProtocol" to language tool dialog"

Revert "cui: add entry "RestProtocol" to language tool dialog"

This reverts commit 70ff8fc992c06edfd6ae60da39cabed8cb56a5c5.
Reason for revert: it is bad UX to add a new field to the LanguageTool
settings dialog, without any explanation. The user will not find out,
that this field can be used for Duden Korrekturserver. Also, for Duden
Korrekturserver the user name field is not necessary. Until we design
a better dialog, I think it would be better not to have this setting in
desktop Office, because it can be confusing.

Change-Id: Id7b031e79e94475de1add295d64ed6b6018f03ae
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/146913
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Ashod Nakashian <ash@collabora.com>