Add missing translatable configs and make translatable photoswipe configs translatable

I'm on it!

Done with this one so far!
@Anybody, when you're reviewing: NOTE that the new update hook is #9008 because of another issue about to be merged having a new update hook #9007! Please merge that one first!

LGTM!

One last thing, we still need to create a links.task.yml, otherwise there will be no translatable tab on the settings page:

- Next, create the link to the translation page on the settings page, using
a "my_module.links.task.yml":
~~~
my_module.settings:
  title: 'my_module Settings'
  route_name: my_module.settings
  base_route: my_module.settings
~~~

I have renamed the update hook, however I'm not sure what you mean with comment #8 - due to the config_translation.yml the translation tab will appear automatically in the form of "Translate 'Photoswipe Settings'" without the need for a manual tab creation via the tasks.yml, at least it worked for me...

@LRWebks not if we only have the photoswipe module installed! Try it yourself by uninstalling all photoswipe submodules and go to the settings page. The translatable tab will only get added, if tabs already exist (which is the case, when activating the dynamic_caption submodule but not when only photoswipe is enabled).

Added the links.task.yml and it works now! Back to review.

LGTM! @Grevil if you should have the time, please take a final look.

Perhaps as @Grevil is currently not able to take a look, we should set it to RTBC or invite someone else from Photoswipe in to take a look...

I'll review and test it when I have the time, thanks!

I am back! Reassigning this issue to me again.

Code LGTM and update hook / functionality works perfect!

Well done @LRWebks!

Automatically closed - issue fixed for 2 weeks with no activity.