Ensure stable ordering within same slot

[KtorZ]

Fixes #65

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• 📍 Refactor: extract serialization / deserialization logic for output reference.

• 📍 Include transaction index within block when folding on blocks.
  Serialization now needs to be adjusted as it currently ignores the transaction index.

• 📍 Rework OutputReference serialization to include transaction index.
  This has a side-benefits of making the database a bit more compact although the marking / removing of inputs may now be slightly less efficient (haven't run benchmarks yet; soon).
  The new index isn't used yet.

• 📍 Order by descending created_at slot & fallback to transaction index when equal.

• 📍 Add specification & supporting code for changing results order
  Going for 'most_recent_first' and 'oldest_first' instead of 'asc' or
  'desc' for more clarity.

  We could do something slightly more elaborate if there was multiple
  criteria to sort on, but only the sorting direction is configurable
  here.

• 📍 re-introduce policy-id and asset-name in API doc, as deprecated parameters.

• 📍 Create Makefile to group common commands and build instructions.

• 📍 Refactor: leverage 'Either a' monad to simplify writing of Http handlers.
  Instead of building a pyramid of pattern matches, we can flatten it all using a do-syntax and an appropriate monad.

• 📍 Wire new 'order' query parameter through the API.

• 📍 Fix dynamic pattern addition end-to-end scenario & add more debugging to the test bench.