Hide transaction list and empty message when loading - Closes #348

[ginacontrino]

What was the problem?

The loading of the transaction list was not smooth, sometimes the empty message was showing, when the transactions where still loading

How did I fix it?

There was nothing implemented yet in the transaction list, so I added an extra condition for the loader.
I also added an extra loading state for the initial transaction request. So now instead of an error message or old transactions, we will just see a white background.

How to test it?

Set your network to slow in the browser, compare my branch with 0.2.0 and load a transaction page. You will probably see the difference.

Review checklist

• The PR solves Transactions list shows No Activity message instead of Loading #348
• All new code is covered with unit tests
• All new features are covered with e2e tests
• All new code follows best practices

[slaweet]

Thanks, Gina