[AndyB] Account upgrade receipt 1.6

Description:
Creates an account upgrade receipt.
Features:

• All phrases start with accountupgradereceipt_ for your convenience.

Setup step 1:
User group permissions
Select the Registered user group. Find the 'Account upgrade receipt' option and set View to Yes.
Setup step 2:
Custom user fields
Create a Custom user field:
Field ID: company
Title: Company
Description: {leave blank}
Display location: Personal details
Display order: 1
Field type: Multi-line text box
Setup step 3:
Options page
Enter 'Purchased from' details into the Options page.