Make Seller's orders list flexible

[haydave]

Is your feature request related to a problem? Please describe.
The implementation of the Seller's orders list is not flexible enough to easily add new columns using custom codes or plugins. It is required to change all columns' width percentages one by one to make it a bit nice looking.

Describe the solution you'd like
Change the implementation so adding new columns will not require updating the styles of the orders list. So if Arcader decides to add new columns or remove ones, will not force the plugin/custom code developer to rewrite the styling of the list.

Describe alternatives you've considered
Seller's orders list can be implemented like Orders/Invoices/Transactions list in Admin dashboard.