sdk: instantiate all Babylon contracts using Babylon SDK

[SebastianElvis]

It would be good to let Babylon SDK 's x/babylon module to instantiate all Babylon contracts. This

• simplifies the BTC staking integration as one does not need a gov prop to set contract addresses in module params
• avoids contracts instantiating each other

[maurolacy]

Duplicate / sibling of https://github.com/babylonlabs-io/babylon-sdk/issues/45.

[SebastianElvis]

Oops lets follow https://github.com/babylonlabs-io/babylon-sdk/issues/45 then