add screen for contract like account screen

[dadaphl]

atm deployed contracts don't have a dedicated screen. I propose to introduce one on which users can see:

• link to its create tx (or include it in the screen)
• list of tx on that contract

Probably adjustments to the middleware have to be made and maybe even SDK changes.

[dadaphl]

In the future we could also have creators of the contract upload the source and get get a "verified" contract for users to have better control to understand what a given contract does