Add y/n option to missing libraries

[krowvin]

CLI Script

cwms-cli

Feature Proposal

If a user does not have a required library, you will see this due to the @requires decorator.

cwms-cli blob list 

Error: Missing module(s):
- `cwms` (install: `cwms-python`) — CWMS REST API Python client [docs](https://github.com/HydrologicEngineeringCenter/cwms-python)

Install missing packages:
    pip install cwms-python

Should the CLI prompt the user y/n to auto install the library?

I.e. something like

Would you like to install missing packages?
    pip install cwms-python

> [Y]es/[N]o: N

Bonus, we can use sys.executable to install it so that it will also respect the current python env.

Thinking we can build this into the @requires decorator