✨🔥 Add `Get-InstapaperArticles.ps1` and `Remove-InstapaperArticle.ps1` and remove the Pocket versions

[brianary]

Use the Instapaper API and create new scripts to manipulate articles. There should be feature parity, but Instapaper also supports folders.

[brianary]

The API uses OAuth1.0a, which is a tricky implementation, and pretty out of date. Maybe use TinyOAuth1?