Update icon names

Updated the following icon names:

- dashicons-admin-site --> dashicons-admin-network
- dashicons-site --> dashicons-admin-site
- dashicons-gauge --> dashicons-admin-dashboard
- dashicons-admin-dashboard --> dashicons-admin-home
- dashicons-camera2 --> dashicons-camera
- dashicons-imgedit-undo --> dashicons-undo
- dashicons-imgedit-redo --> dashicons-redo
- dashicons-xit --> dashicons-dismiss
- dashicons-arrow-up --> dashicons-upload
- dashicons-arrow-down --> dashicons-download
- dashicons-network --> dashicons-networking
- imgedit --> image, write out full name (rleft --> rotate-left)
- graphs to --> chart-bar, chart-line, chart-area, chart-pie
- change everything with 1/2/3 to alt, alt-2
- change all arr to arrow
- remove twitter-alt b/c it's not correct branding