As a user of the Mismatch Finder and Query Builder I want to work with the site in my language.
**Problem:**
We currently only support language switching for our Single Page Applications (specifically Mismatch Finder and Query Builder) via URL parameter. We need to also offer it via the UI. This ticket is for investigating how we can do this.
**Acceptance criteria:**
[ ] we know how our SPAs can support language switching in the UI
**Notes:**
* Some discussion already happened in the comments of T323683 and T289426 that needs to be reviewed as part of this.
* Assumptions/routes to validate:
* 1. We can reuse the existing Language selector component implemented by the Language team in our SPAs (in use by Vector 2022);
* 2. We can create a minimal/MVP version of a new Vue Language selector tool, and
* 2.1. contribute it to Codex or
* 2.2. consider it a temporary solution to be replaced later