Split ICU4X data generation from boa_icu_provider

[jedel1043]

Thankss to #3681 I realized we could benefit from isolating our datagen dependencies from boa_icu_provider, which is why I decided to create a separate crate to run the datagen step.

This PR also adds a new flag to exclude the data from boa_engine if the user wants to.

Size comparison

Main

❯ ls -l core/icu_provider/data/icudata.postcard
❯ -rw-r--r-- 1 jedel users 16910774 Feb 18 22:05 core/icu_provider/data/icudata.postcard

PR

❯ ls -l core/icu_provider/data/icudata.postcard
❯ -rw-r--r-- 1 jedel users 16417284 Feb 19 00:29 core/icu_provider/data/icudata.postcard

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	50,268	50,268	0
Passed	42,565	42,565	0
Ignored	1,570	1,570	0
Failed	6,133	6,133	0
Panics	0	0	0
Conformance	84.68%	84.68%	0.00%

[HalidOdat]

Besides the comment below this looks good to me!

[raskad]

In the latest commit you removed the intl_core feature but did not revert the cfg annotations from intl_core to intl. I think that is why all intl tests are failing on the latest commit right? @jedel1043

[jedel1043]

Yep, yesterday I pushed my changes without checking CI because I was a bit sleepy. Will fix the tests when I have the time.