Merge 1.1.0 changes back to master.

Conflicts:

 * extensions/guacamole-auth-cas/src/main/resources/guac-manifest.json
 * extensions/guacamole-auth-duo/src/main/resources/guac-manifest.json
 * extensions/guacamole-auth-openid/src/main/resources/guac-manifest.json
 * extensions/guacamole-auth-quickconnect/src/main/resources/guac-manifest.json
 * extensions/guacamole-auth-radius/src/main/resources/guac-manifest.json
 * extensions/guacamole-auth-totp/src/main/resources/guac-manifest.json
 * guacamole/src/main/webapp/translations/de.json