[#254] [#256] Running of contract in DAP

Description

Running of DAP contract, with reporting of current location and stepping.

Should be merged after !484 (merged) and !495 (merged). Currently contains a cherry-picked commit from !495 (merged), this should be removed after that PR is merged.

Related issue(s)

Resolves #254 (closed)

Resolves #256 (closed)

✅ Checklist for your Merge Request

Related changes (conditional)

• Tests (see short guidelines)

  • If I added new functionality, I added tests covering it.
  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

• Documentation

  • I checked whether I should update the docs and did so if necessary:
    • Root README and other README.md files
    • Haddock
    • docs/
  • I updated changelog files of all affected packages released to Hackage if my changes are externally visible.

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