feat: Make protocol registration a configurable user preference

[oblivioncth]

Prevents the launcher from forcefully overwriting an existing registration for the "flashpoint://" protocol if the user wants to use another application for that.

The default value true keeps existing behavior. Setting the value to false not only prevents the launcher from setting itself as the protocol handler, but will remove a prior registration of itself if present.

The non-English strings are all via Google Translate, which I figured was better than nothing.

[oblivioncth]

Improved error reporting by accounting for Electron quirks.

[colin969]

Looks good, but I'll double check later today.

You shouldn't include non-english strings here. That's CrowdIn's job. Note for the future.

[oblivioncth]

You shouldn't include non-english strings here. That's CrowdIn's job. Note for the future. Noted. Forgot about that service.

To clarify exactly how this should be handled in the future, should one: 1) Not modify the the non-English lang/*.json files at all (i.e. leave out the new variable from them entirely) 2) Add the new variable to the non-English files as an empty string. 3) Add the new variable to the non-English files with the string as just a copy of the English one.

I did see some English in the translation files so I'm guessing 3?

Finally, do you want me to drop/alter the translations in accordance with the above proper action from this PR specifically? Or should I leave this one alone?

[colin969]

1. Language files except for English should not be touched.

It'd be easiest to apply the lang files for non-english from the release branch to yours to deal with conflicts.