<!---
Thank you for contributing to Boa! Please fill out the template below, and remove or add any
information as you feel necessary.
--->
This Pull Request enables support for `no_std` targets on some of our sub-crates. I intentionally left out `boa_ast` and `boa_cli` because they're the largest crates we have after `boa_engine`.
`boa_gc` is a monster on its own, because we'll need to design a `no_std` multithreaded GC.
Anyways, this changes the following:
- Adds support for `no_std` on `boa_unicode`.
- Adds support for `no_std` on `boa_profiler`.
- Adds support for `no_std` on `boa_interner`.
- Adds support for `no_std` on `boa_icu_provider`.
José Julián Espina
097f85e409