We have initTranslations() for binding an extension's
gettext domain, but nothing to help with using gettext
from an extension.
Such help would be useful though, as an extension that
calls textdomain() like a normal application would
inadvertently changes the default domain for the whole
gnome-shell process.
Instead, extensions have to use domain-specific versions
of the gettext functions:
```js
const Gettext = imports.gettext.domain('my-extension');
const _ = Gettext.gettext;
```
Make this a bit easier by adding those functions directly
to the extensions object when initTranslations() is called,
then expose helper functions for calling them.
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2594
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1941>
The Extensions app code is now independent enough from the rest of the code
base to move it to its own subprojects, like we did for the extensions-tool.
This allows for stand-alone builds of the app, which we are about to use
for distributing it as flatpak.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1133
I misremembered that imports.package.start() would set up the correct
gettext domain, but the module only provides a convenience method
for doing that.
Use it to bring back translations in the Extensions app, whoops.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1108
