Fix setExecutable error on macOS (Monterey +)

[Bargsteen]

Purpose

Closes #301

With #243, we pass a closure for accessing the blobstore across FFI. On macOS Monterey (and very likely future versions of macOS) this causes the signed node to be unable to run (see #301). This is because of an issue in GHC: https://gitlab.haskell.org/ghc/ghc/-/issues/18376.

This fix is a workaround, that slacks the restrictions on the sandbox that signed macOS apps are put into.

Changes

• Adds an entitlements file which allows unsigned executable memory (should be removed once the GHC issue is fixed)

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.