Ability to create more types of descriptors

[BitcoinZavior]

Large variety of descriptors are possible reference: https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md

createDescriptor should be able to create as many of these descriptors as possible.

[i5hi]

We would need to add two things for this:

• policy compiler
• newBip84Sh() method to the Descriptor class to support wsh script type

[i5hi]

This would then also require the policy_id function to be exposed. It would up the user to know what they are doing if they venture into creating complex scripts and they would have to know how to parse their policy and specify which nodes in the policy they are signing for.

[BitcoinZavior]

Yes, we will probably follow bdk-ffi api which in turn follows bdk api.