feat!: prevent implicit burn

[MujkicA]

Summary

TransactionBuilder will return an error on .build() if the transaction has input assets that don't have a corresponding change output. To enable burning, .enable_burn() flag has to be set to true.

Breaking Changes

Building transactions that implicitly burn coins will result in an error.
adjust_for_fee will add a base asset output consistently

Checklist

• All changes are covered by tests (or not applicable)
• All changes are documented (or not applicable)
• I reviewed the entire PR myself (preferably, on GH UI)
• I described all Breaking Changes (or there's none)