*mozilla: Allow appending of Additional items

[HUMORCE]

USAGE:
Create a directory named addition in app's persist directory (e.g. ~\scoop\persist\firefox\addition), and put files/configs/etc. into the directory.

Items of addition directory will be copied to app root directory by install script every install/update.

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Any items that overwrite the original files are NOT RECOMMENDED.

see also: https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig

Closes #8016

• I have read the Contributing Guide.

[github-actions]

All changes look good.

Wait for review from human collaborators.

firefox-esr

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• Autoupdate
• Autoupdate Hash Extraction

firefox

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• Autoupdate
• Autoupdate Hash Extraction

seamonkey

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• Autoupdate
• Autoupdate Hash Extraction

thunderbird

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• Autoupdate
• Autoupdate Hash Extraction

waterfox-classic

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• Autoupdate

waterfox

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• Autoupdate

[HUMORCE]

@Sei-lus try and feedback.

[Sei-lus]

@HUMORCE will give feedback as soon as I can.

[Sei-lus]

Ok, as good a time as ever, was waiting for the pull request to be added. Testing now.

[Sei-lus]

The addition folder had to be manually added. I would recommend to add documentation by default at persist.

i.e: Persist for firefox generates distribution and profile folders. I would recommend putting a .txt file indicating the usage of "addition" and adding "addition" folder by default to hint the users. Will have to wait firefox to go to 98 to see if it is working but I set it up.

[HUMORCE]

The addition folder had to be manually added. I would recommend to add documentation by default at persist.

people who want to modding these apps can find the sugar. 🥶