increase use and utility of zkApp CLI: document the value statement, troubleshooting, versions

[barriebyron]

I am a patch version behind zkApp CLI and got an unexpected result with

@ymekuria recommended to upgrade the zkApp CLI version, which got me to thinking.

I thought I remembered a prompt to upgrade my zkApp CLI, but maybe I imagined it. Questions:

1. When do the "get the new version" prompts occur, if ever? A user sees a message to upgrade cli versions if there is a newer minor version of the cli and snarkyjs. For example, If a user is running the zkapp cli version 0.8.5 but the current version is 0.9.2, they will see a message to update their cli and snarkyjs versions. If they are running 0.8.5 but there is a version 0.8.7, they will not see a prompt to update.
2. How would a dev know to upgrade zkApp CLI?
3. How would a dev know to upgrade SnarkyJS?
4. If SnarkyJS is included in every project, then the version of zkApp CLI is quite important, right?
5. Would it ever be required to go back to an earlier version?

Include:

A high-value page will be helpful for our developers: I envision an explainer intro topic for zkApp CLI and best practices: upgrade, run npm install every now and again, and so on

If you ever run into an error it is always recommended to try upgrading the cli and then trying things out. npm update -g zkapp-cli

[barriebyron]

the zkApp CLI README now includes this information

work in https://github.com/o1-labs/zkapp-cli/pull/455 can be leveraged for docs, wdyt @garwalsh