feat: support allowed github urls

[mdonnalley]

What does this PR do?

• Support allow-listed github urls (e.g. https://github.com/oclif/plugin-version)
  • only https://github.com/<org>/<repo> is supported. You cannot use https://github.com/<org>/<repo>.git, https://github.com/<org>/<repo>#commit, etc...
• Display plugin name in prompt instead of This plugin

What issues does this PR fix or reference?

@W-15313997@

[iowillhoit]

QA NOTES

Install logging

• 🟢 Plugin name is now shown with an npm install
  • 🟢 sf plugins install foo
• 🟢 An org/repo install shows the full github url in the message
  • sf plugins install oclif/plugin-version
• 🟢 Prompts with full url with version
  • sf plugins install https://github.com/oclif/plugin-version.git#2.0.11
• 🟢 Prompts with full url with branch
  • sf plugins install https://github.com/oclif/plugin-version.git#ew/testing-plugin-plugins-npm-branch-installs
• 🟢 Prompts with "github notation"
  • sf plugins install github:oclif/plugin-version
• 🟡 Nitpick: there is an extra , at the end of the confirmation: [...] Do you want to continue the installation?, (y/N)

Allowlisting

• 🟢 Can allowlist github:oclif/plugin-version
• 🟢 Can allowlist https://github.com/oclif/plugin-version
• 🟢 Can allowlist https://github.com/oclif/plugin-version.git
• 🟠 You can install with sf plugins install oclif/plugin-version but cannot allowlist with oclif/plugin-version
  • NOTE: oclif/plugin-version does work with https://github.com/oclif/plugin-version in the allowlist