`tst_languageSettings`:
- Feature and basic scenarios definition: Change language by selection and change language by search.
- Added `StatusLanguageScreen` class and related methods to change and validate language.
`SquishDriver`:
- Added support to scroll at a specific list view index.
- Added support to directly type into a focused element.
`settings_names.py`:
- Added support for object names related to `side bar` options.
- Unified some nomenclature related to settings objects.
`LanguageView`:
- Updated to allow registering the change on Linux before the restart popup is shown so the language test can work.
Closes#6903
Note: interaction between clients is not tested here to avoid dependency
on mailserver. When mailserver is mocked more comprehensive tests should
be provided, that is: verify if identity properties are propagated
and read correctly between two different clients.
closes: #6950