Create .tar.gz package deterministically using Python's "tarfile"
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A development of #12108, creates a .tar.gz package using the `tarfile` and `gzip` modules, without external dependencies. Fixes#11981.
Also this fixes the issue when the existing `resources/` directory didn't allow to create a new package and failed with "File exists" error.
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- [X] These changes fix#11981 (github issue number if applicable).
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Change colons to dashes in package name
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Updating packaging so that packages use '-' instead of a ':'
r? @ConnorGBrewster
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- [X] `./mach build -d` does not report any errors
- [X] These changes fix#11984 (github issue number if applicable).
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- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because they are updating packaging
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* Split package commands into their own file
* Delete spurious files from build dir
* Create runservo.sh to invoke servo with the right browserhtml incantation
* Tar it all up with the date and time in the filename
