[clarity] Clarity-Bitcoin v5 (optimization)

[setzeus]

Feature Description
This issue is a sister issue & marker for visibility for @MarvinJanssen to optimize the Clarity-Bitcoin library (aka Clarity contracts). Since the contract is heavily-used, it makes sense to prioritize a cost optimization.

Proposed Solution
Tbd - not entirely sure how the optimization will occur.

Additional Context
Same #3961 , due to the lack of a central home (first Jude's repo, now Friedgers), I'm not entirely sure where this v5 will live so we must make sure to link that repo back here to appropriately track & close this issue.

[setzeus]

TODO: set up a scoping session to define a tighter / clearer scope.

[setzeus]

• Main optimization in v4, looking for more options

[setzeus]

Update on #3961 , paired effort to finish there before optimizing.