Add create-github-app-token plugin implementation - #1

Add create-github-app-token plugin implementation#1

lox wants to merge 6 commits into

mainbuildkite-plugins/create-github-app-token-buildkite-plugin:mainfrom

move-plugin-to-buildkite-pluginsbuildkite-plugins/create-github-app-token-buildkite-plugin:move-plugin-to-buildkite-pluginsCopy head branch name to clipboard