[bitcoinsuite-core] Add script to ASM feature

Summary:
This implements the Display trait for the Script class to show as ASM code.
Shamelessly extracted from https://github.com/givelotus/bitcoinsuite/blob/master/bitcoinsuite-core/src/script.rs#L281.

Test Plan:

cargo test -p bitcoinsuite-core

Reviewers: #bitcoin_abc, tobias_ruck

Reviewed By: #bitcoin_abc, tobias_ruck

Subscribers: tobias_ruck

Differential Revision: https://reviews.bitcoinabc.org/D19156