Add core GitHub commands

[pcgeek86]

We need to fill out some of the core commands for interacting with GitHub.

Core

• [ ] We need to figure out how to handle data pagination

Authentication

• [ ] Support authentication in Microsoft Azure Automation runbook service, using PSCredential asset type
• [x] Encrypt GitHub Personal Access Token on-disk in JSON configuration file
• [ ] Add support for multiple usernames and Personal Access Tokens
  • Enable user to switch between contexts
  • Enable user to specify a GitHub profile during each command call

Repositories

https://developer.github.com/v3/repos

• [ ] List the authenticated user's GitHub repositories
• [ ] List a specific user's public GitHub repositories
• [ ] List all public repositories
• [x] Create new repositories
• [ ] Edit / modify properties of existing repositories
• [x] Delete existing repositories
• [ ] List contributors
• [ ] List languages in project
• [ ] List branches
• [ ] Get a specific branch
• [ ] List Git tags on a specific repository

Pull Requests

https://developer.github.com/v3/pulls/

• [ ] View outstanding Pull Requests for an owner / repository
• [ ] Merge one or more Pull Requests (one PowerShell command)
• [ ] Update a Pull Request (title, description, state)
• [ ] Create a Pull Request

Search

https://developer.github.com/v3/search/

• [x] Search for GitHub repositories
• [ ] Search for GitHub issues
• [ ] Search for GitHub users
• [ ] Search for code

Issues

https://developer.github.com/v3/issues/

• [x] Create new GitHub issues
• [ ] Close or re-open GitHub issues
• [ ] List all or individual issues
• [ ] Lock and unlock issues

Milestones

https://developer.github.com/v3/issues/milestones/

• [ ] Create a milestone
• [ ] List all milestones
• [ ] Get a specific milestone
• [ ] Update a milestone
• [ ] Delete a milestone

[exactmike]

Pull request I posted today addresses:

• List the authenticated user's GitHub repositories
• List a specific user's public GitHub repositories I think with a little more effort and another parameterset we could also address
• List all public repositories