Optimize registry

[Vectorized]

• pragma solidity ^0.8.4; is the minimum for custom errors.

• Create2.computeAddress -> ERC6551BytecodeLib.computeAddress so that it is actually a single file. This makes it easier to verify in case OZ updates their code, such as bumping their solidity pragma. I'd recommend including the bytecodehash in the compilation config as per default to prevent comment vandalism.

• Feel free to reject / delete anything for simplicity if it makes things simpler.

• testDeploy() gas: 145709 -> 143826 -> 143551

OCD nits:

Since the registry is gonna be at an immutable address forever...

• Comments should have consistent capitalization, periods, formatting. Best is to have a period after every sentence.

• Try to avoid underscores prefix or postfix if not necessary to avoid variable name collision.

[sullof]

This looks great.

[jaydenwindle]

@Vectorized this is awesome, thanks so much for the PR! Eeked out a few more gas savings (143551 -> 142722) and fixed the merge conflicts + nitpicks here. Would love your feedback on these changes :)

[jaydenwindle]

awesome stuff @Vectorized, thanks a ton!