Rename 'Lead Owner'

[joshuarestivo]

This tracks upstream issue: frappe#398

The term 'Lead Owner' is confusing and potentially misleading. The fact that 'Lead Owner' and 'Assigned To' fields exist and have linked functionality creates confusion for users. The confusion is especially apparent when Lead Owner is carried forward into a Deal.

Can we rename this field to 'Account Owner'? This would reduce the ambiguity between it and 'Assigned To'. It would also make more sense as the Lead progresses through the system. If you're integrating with ERPNext, for example, this field may need to be updated as the account is handed off to inside sales and/or support teams. 'Account Owner' would make a lot more sense in this case.

I realize that the field label could be updated as a band-aid but that introduces opportunity for confusion in itself.