Implement `/main/smart-contracts/list` tab

[aesedepece]

User story

As a Witnet user, I expect the Sheikah interface to show a history of all the smart contracts that I have ever deployed to the Witnet network.

Motivation

As depicted in Issue #17, the "Smart contracts" section has a tab called "My contracts". This tab lists an historic of all the smart contracts ever deployed by the user.

Considerations

• We can rename "my contracts" for "history" if we consider that it makes more sense and sounds better.
• For demo purposes, this section will be completely mocked in the Sheikah Technology Preview. We are putting SVGs in place and deferring implementation of the actual components as an only-if-we-have-spare-time-at-the-end-of-the-sprint thing. SVGs will be available in our kb team folder.

Tasks

• Analyze all the screenshots from Issue #17 .
• Create the route for this tab.
• Implement the tab.

[aesedepece]

Solved as of de6fae3cdef59fdd5944b21f90ba466c48bd8a43.