[Howto] Per user quota edit within ispcp when using dovecot

[JCD]

Thanks for this nice piece of work!
I took your proposal and modified it a little bit. I think the better option is to incorporate the quota into the email account settings where password and forward can be changed. This would keep all settings together and as quotas aren't changed very often there is no need to give it an extra button.

Below you can find my proposal. It is patched against 1.0.5. Here are my changes:

* Quotas can be changed in the account settings
* Quotas can be given in MB. Conversion to Bytes is done during processing.
* Variable names were changed to adapt to the naming scheme of the other variables
* The field descriptions were adjusted to have the same appearance like those of the other fields where a unit value is inserted
* Template files are now XHTML compliant