Implement character transfer SKU for the shop

We could use the following command via SOAP to implement it

`.character changeaccount [accountName] [player]`

[player] can be characterName or characterGuid (to be verified)

Optional configuration:
- allow character transfer only to non-fresh accounts (ex. accounts older than 30 days)

Use the shop SKU flow and the SOAP command `.character changeaccount [accountName] [player]` as the starting points. Verify whether `player` accepts a character name, GUID, or both, and determine where the optional account-age restriction belongs. Done means the SKU performs the transfer and the non-fresh-account rule is configurable if implemented.

Written by the indexing model from the issue text.