Forbid clients to add funds to personal account if they do not order services

[The Wishmaster]

Add an option to hide the buttons and links to add funds to a
personal account on the user level. This will help to avoid
situations when a client first credits his account, does not buy
anything and then asks for money back.
Hide the following links and buttons:
- “Credit account” on the Homepage;
- “Pay” in the “Personal account information” form;
“Add” in the “Credits/Payments” module.