Added section for plugin admin initialization

Added section for general admin initialization processes for the
plugin. Initial commit includes call for plugin data, which is
currently used to grab the plugin version in other functions.
Renamed JavaScript file

Renamed ‘edit-user-bio-editor.js’ to ‘edit-user.js’
Removed plugin environment data section

Removed plugin environment data section, and relocated certain portions
of the code to main admin file.
Renamed file

Renamed JavaScript file from ‘edit-user-bio-editor.js’ to ‘edit-user.js’
New Class file

Created new Class file for managing multiple post authors inside
WordPress admin.
Renamed file

Renamed file from ‘edit-user-bio-editor.js’ to ‘edit-user.js’