Export `containers`-based solution

Probably do it only after multiple public library support is added to `cabal`.

Also, maybe it will become possible to abstract interface with Backpack and remove code duplication in benchmarks and test-suites? :thinking:

Start by reviewing the current cabal setup and how the benchmarks and test-suites are organized. Check the feasibility of exporting a containers-based solution after multiple public library support is added to cabal, and determine whether Backpack can remove duplication; done requires a defined export approach and corresponding updates.

Written by the indexing model from the issue text.