Create CLI command builder with metatable

[wd60622]

Describe what this PR does / why we need it

This adds a metatable to the octo.gh module which allows for building commands more closely to the CLI commands.

For instance,

local gh = require "octo.gh"

local print_response = function(stdout, stderr)
  vim.print(stdout)
  vim.print(stderr)
end
local opts = {
  cb = print_response
}

-- gh auth status -a
gh.auth.status { 
  a = true,
  opts = opts,
}

-- gh issue list --json author,labels
gh.issue.list {
  json = "author,labels",
  opts = opts,
}

-- gh pr list --search "is:merged -label:no releasenotes"
gh.pr.list {
  search = 'is:merged -label:"no releasenotes"',
  opts = opts,
}

-- gh pr view 810 --json author,labels,title,url
gh.pr.view {
  810, 
  json = "author,labels,title,url",
  opts = opts,
}

Note

Anything in the opts table will be passed to the run function

Note

There is no validation that happens on the commands. If someone has extensions installed, They will be able to be used
gh.milestone.list will work if the extension is installed
gh.copilot.explain { "How to install nvim" } if the copilot extension is installed

Warning

Commands like gh.run.list will not work due to it being used by the module already...

Does this pull request fix one issue?

Describe how you did it

Have a metatable for the octo.gh module that allows for building commands more closely to the CLI commands.

Describe how to verify it

Special notes for reviews

Checklist

• Passing tests and linting standards
• Documentation updates in README.md and doc/octo.txt