Restore Base Encoder package

[poke]

This restores the Base Encoder package which has been marked as “missing“ on the website and has been removed from the channel in #8844.

The original repository is gone but the fork by @socsieng is still available and the original author agreed to have the package point to the fork as part of the discussion in #5016.

[deathaxe]

https://packagecontrol.io/packages/StringUtilities at least provide base64 decoder and encoder.

I wonder if it would make more sense to add missing base16 and base32 converters to that package instead.

That said code of existing "Base Encoder" looks rather dated.

If we want to re-add it, I'd suggest to also revise the code base.

1. make use of edit_settings
2. opt-in to python 3.8 for ST4
3. replace the threaded set_status() call by window.status_message()
4. maybe drop default key bindings as it is easier to add them than to get rid off.

FWIW, we can use SublimeText org to maintain and ship a revised version of that package (or StringUtilities).

[deathaxe]

Also found https://packagecontrol.io/packages/StringEncode with base64 encoder/decoder.