[posm]: Create a view only library specific to posm positions

[snreynolds]

Component

Position Manager

Describe the suggested feature and problem it solves.

This library should use StateLibrary.sol but be specific to querying information about a tokenId's position and should abstract away most under-the-hood logic (like the tokenId is used as a salt)

WRT this issue, we should maybe consider implementing the mapping from tokenId => positionId so this lookup is easier.

Also consider adding view functions for calculating fee growth of a specific position.

Describe the desired implementation.

No response

Describe alternatives.

No response

Additional context.

No response

[linear]

PROTO-332 [posm]: Create a view only library specific to posm positions

[saucepoint]

Decided to provide getters instead of extsload + library helpers because

1. we arent as constrained by bytecode as PoolManager
2. there's very little state on posm itself

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partially closed with #270 where a getter was added to access liquidity

still need a view function for fee growth, which will be useful for integrators and clients