improve sortedCdps pagination functions

[rayeaster]

address https://github.com/cantinasec/review-badgerdao/issues/35

• add lastly-visited CDP id as the next pagination startNodeId for public functions that allow parameters of startNodeId and maxNodes in the signature
• add fuzz test in foundry to walk-through the expected pagination usage

[dapp-whisperer]

@rayeaster can you advise on the merge conflict that arose from merging this? https://github.com/Badger-Finance/ebtc/pull/658/files