feat: ask confirmation before submitting transaction

[mFragaBA]

closes #257

Summary of changes

• Shows the TX details before proving and submitting the tx f0fb419
• Adds a "--force" flag to the new transaction command to skip the confirmation step (ideal for non-interactive environments) b712ede

Steps to test

You can start from either a fresh client or an existing one. To test this change, you can run any transaction (i.e miden-client tx new ...) and check that it asks for confirmation and it prints a summary of the changes applied to the account. Enusure that if you submit a "y" or "Y" the transaction gets proven and sent to the node, and doesn't do anything else otherwise (no state shall be changed in that case)

Here's how it would look like:

After confirmation:

[mFragaBA]

Looks great! Thank you!

Some thoughts for the future (not for this PR): seeing this now, we should probably add more info about the transaction (not just account delta). For example, something along the lines of "this transaction will consume notes a, b, c, have the following effects on the account, and produce notes x, y, z. Let's create an issue for this.

created #316