[#209] Clean up indigo managed ledger

Description

Problem: Currently Indigo version of ManagedLedger is implemented very similar to the Lorentz version and doesn't fully use Indigo features, e.g. it does constructT instead of passing multiple arguments the function.

Solution: Update implementation.

Apart from that ManagedLedger implementation was made storage-polymorphic (the same way as Lorentz version), so now we can reuse its parts in the other projects.

Related issue(s)

Resolves #209 (closed)

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