Add edit buttons to Users index

[maebeale]

Add edit buttons (with pencil icon) to left of user emails on Users index that to to that User's rails edit page.
This page should only be viewable to people with MANAGE_USERS permission.

[RachelWyatt]

Hi @maebeale, is this for /user_management (screenshot below)?

If so, a couple of questions:

1. The screenshotted page is in the code as a show page but I think is really acting as more of an index page. Is there any sense in refactoring that? Is there potential need for a show page for user management? Or would that just end up being /users/show?
   1a. Another option -- should this page be moved to users/index? Right now it doesn't look like User Management has any special functionality, but I didn't know if that was a plan for the future.
2. Should the edit page the button links to be at /user_management/1/edit or /users/1/edit?

Or if I'm looking at the totally wrong path just let me know :)

[RachelWyatt]

For this PR I'm:

• Adding users_management/editpage and route to allow a user with the MANAGE_USERS permission to edit other users' permissions. User with MANAGE_USERS permission should be able to add or delete all permissions for each user.
• This will not be the place for editing a User's name, e-mail, etc., or deleting a user. That functionality should live in Users and User_management should be just for handling permissions.