Consolidate shell scripts

[2byrds]

We are repeating a significant amount of logic across test.sh and test-multi-user.sh Consolidate them so that we have the flexibility to:

• [x] One test.sh (called test.sh) that is capable of single/multisig, single/multi-user, and configuration via json
• [x] Remove multiuser.sh
• [x] Improve user messages to understand how to properly configure the scripts