feat: print note and account source code on show commands in the CLI

[tomyrd]

In #492 we removed the source code section when when showing notes and accounts in the CLI because the ProgramAst type was removed in favor of a MastForest. Is there a way to retreive the original source code from it?

[bobbinth]

Currently, there is no way to retrieve the original MASM from MAST - but there are two things we can do:

1. For now, we can pretty-print MAST - it is slightly lower-level than MASM, but it is much better than ones and zeros (and is still sort of human readable).
2. Once 0xPolygonMiden/miden-vm#1440 is addressed in miden-vm, we'll be able to optionally include the original source code into MastForest. At that point, we can print out MASM when it is available.