Update to v0.15.0

[JordanMartinez]

Description of the change

Backlinking to purescript/purescript#4244

Migrates FFI to ES modules

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Checklist:

• Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0000)")
• Linked any existing issues or proposals that this pull request should close
• Updated or added relevant documentation
• Added a test for the contribution (if applicable)

[JordanMartinez]

This PR was created by running the following scripts from purescript-ecosystem-update. Some of these scripts might not work on Mac computers:

./init.sh
./forkAll.sh - this currently only forks the prelude and newtype library since I want to confirm that the changes I'm automating are correct
./compile.sh 0 prelude
./pr.sh 0 prelude

[JordanMartinez]

Oh, and CI is failing because pulp hasn't been migrated to work on ES modules yet.

[JordanMartinez]

We'll need to port purescript/spago#846 and purescript/spago#856 to pulp. However, pulp is still on Travis CI.

[JordanMartinez]

I'm closing this PR. See working-group-purescript-es/purescript#16

I've saved the work I've done here via the es-modules-libraries branch and es-modules-continue branch.