Refactor: decouple config, sdk, and client

[bap2pecs]

context

https://github.com/babylonchain/babylon-da-sdk/pull/38#pullrequestreview-2155195317

LGTM! In general, I think we can start to refactor the project a bit in terms of architecture in subsequent prs. For example, config is now mixed with client. Many structs are mixed with sdk along with client methods

https://github.com/babylonchain/babylon-da-sdk/pull/45#discussion_r1666279613

Suggest we formalise the mock procedure for unit tests, like what we did in finality provider

tasks

• [x] https://github.com/babylonchain/babylon-finality-gadget/pull/55
• [x] https://github.com/babylonchain/babylon-finality-gadget/pull/56
• [x] get rid of test dependency on stub cw contract

[bap2pecs]

let's also rewrite all tests to not depend on anything external. so we will decouple from:

• BTC mainnet RPC
• Stub contract deployed on Sei

right now make test and make run are both broken. but since we are already covering this SDK in the e2e test in FP repo, I suggest we only do mocked unit test here

cc @lesterli @parketh wdyt? (example: #45)