Add Edit User permission to permissions grid

[tankerkiller125]

Fixes #1845

Changes proposed in this pull request:
This change adds the User Edit permission to the permissions panel in the administration view

Reviewers should focus on:
General code, this is my first pull request for Flarum, the lang-eng repo will also have a pull request that adds the translation for the label

Screenshot

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run php vendor/bin/phpunit).

Required changes:

• Related core extension PRs: Add translation for Edit User Permission lang-english#145

[vingrad]

Thanks for you contributing, but please do not commit the files in the dist directory.

Flarum's front-end code is written in ES6 and transpiled into JavaScript. During development you will need to recompile the JavaScript using Node.js. Please do not commit the resulting dist files when sending PRs; this is automatically taken care of when changes are merged into the master branch.
Reference: https://flarum.org/docs/contributing.html#development-setup

[tankerkiller125]

I've undone the commit and force pushed a new one that only contains the src changes, no dist files are included with the change now.

[franzliedke]

Code looks good, but let's not merge this until the discussion in #1845 has been resolved.

[franzliedke]

I am closing this for now, until we have reached a decision in #1845.

@tankerkiller125 Thanks a lot for your contribution! If we decide to move forward with this, we will surely reactivate this. I am just trying to keep the number of open PRs down. I hope you understand. 😉 Have a great weekend!

[franzliedke]

@tankerkiller125 Thanks and congrats!