Remove mclient.el from the Projects page

I'm removing this from MELPA since it's buggy, unmaintained, doesn't work with e2e and I don't have
bandwidth to fix it right now. :(

supporting-docs/projects/2015-10-01-mclient.el.md

@@ -1,14 +0,0 @@
----
-layout: project
-title: matrix-client.el
-categories: projects client
-thumbnail: https://matrix.org/blog/wp-content/uploads/2015/10/mclient1-400x284.png
-description: A Matrix.org frontend for Emacs!
-author: Ryan Rix
-maturity: Alpha
----
-
-![screenshot](https://matrix.org/blog/wp-content/uploads/2015/10/mclient1-1080x365.png "{{ page.title }}")
-
-# {{ page.title }}
-`matrix-client.el` is a Matrix.org frontend for Emacs. For more information and install instructions visit [the MELPA Emacs package repository](https://melpa.org/#/matrix-client). The code is available at [https://fort.kickass.systems/git/rrix/matrix-client.git](https://fort.kickass.systems/git/rrix/matrix-client.git).