Update generate library command

[iowillhoit]

TODO: Remove branch reference

What does this PR do?

Hides the dev generate library command. Intended for internal use, externals could use it with some changes.
Replaces the message import in the template forcedotcom/library-template#8

Testing

• Clone branch
• yarn build
• cd ..
• Run ./plugin-dev/bin/run.js dev generate library
• Inspect the created library
  • Will be in a directory matching the Name you provide.
  • Run yarn build
  • Run yarn test
    • Note, link-checker might fail since this is not Open Source yet. Running CI=1 yarn test will skip link-check
  • Test in node repl

node
# enters repl
const { Hello } = require('./lib/index.js'); 
const hello = new Hello();
hello.greet('Codey');
# Prints 'Hello, Codey'

What issues does this PR fix or reference?

@W-15235736@

[iowillhoit]

Remove branch ref before merging

[mdonnalley]

idea: make the branch an env var and/or flag for scenarios like this where we want to test the generator against a different branch

[mdonnalley]

QA
Setup: checkout, yarn && yarn build, sf plugins link --no-install

sf dev generate library

• accept default @salesforce
• accept default forcedotcom

Time to build a library!
? Npm Scope (should start with @) @salesforce
? Name qa-library
? Description a library for qa
? Github Org forcedotcom

🟢 Generates library
🟢 yarn build
🟢 yarn test (fails with link checks as expected)
🟢 can run in node repl

node
# enters repl
const { Hello } = require('./lib/index.js'); 
const hello = new Hello();
hello.greet('Codey');
# Prints 'Hello, Codey'

🟢 can yarn link to another library

yarn link
cd another-lib
yarn link @salesforce/qa-library

in index.js

const {Hello} = require('@salesforce/qa-library');
const hello = new Hello()
console.log(hello.greet('Codey'))

❯ node index.js
Hello, Codey