Remote data fixes and next steps

[hugo-stacks]

Context

Remote data (aka MXS: mainnet execution simulation) allows developers to simulate a transaction in Simnet as if it was executed on Mainnet (or Testnet), at a given block height.
In other words, it forks Mainnet.

It's handled in the datastore, where contract metadata and marf data are fetch through stacks-node http api calls.

Use case: run clarity unit tests against a real set of data, without handling fixtures and state warming locally.

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Clean up task

• A lot of the complexity of this feature comes from handling at-block calls, and fetching/handling past data. at-block is no longer supported in Clarity, so we could just remove it for future versions of Clarinet, and greatly simplify this part of the code base

Fixes

• get-block-info doesn't resolve tenure_height in epoch 3.x #1999

Perf consideration

• Because all metadata and data are immutable, they can be cached on disk. This is already the case for metadata, the same could be done for all marf values

[hugo-stacks]

This issue replaces #1646, it can still bring some context, I'd recommend to take a look, for context