[Feature Request]: Plugins should be able to extend tinymce

[HowToMeetLadies]

Feature Description

As a plugin developer, I would like to be provided with a way to deploy tinymce plugins.

For example, by including a tinymce.script.js file from the plugin directory.
These plugins would then be integrated into the user configuration by hand.

You could also let the user choose where to display commands. For example, a dropdown with the selection ["hide", "toolbar1", ...]. The commands would then be provided in the spec, for example: { "assets": { "tinymce": { "fire" : "Fire" } } }

---

This would allow me to add a button to the ImageComparison plugin and the user would no longer have to manually add the wrapper into the HTML. For the Footnotes plugin I could provide a version similar to the toc plugin. etc..

[dziudek]

Similar to #1353 - this feature is in our plans in v.0.46