A loading indicator should be displayed while fetching the list of transactions

[sallymoc]

Current

1. When reloading the transactions page, it's displaying "No transactions found" label during fetching the list of transactions as shown in the screenshot below.

2. After some seconds, it's loading the local stored pending/failed transactions at the top but still displaying "No transactions found" below as shown in the next screenshot.

3. Finally, the local and the transactions fetched from the rpc are displayed together after some seconds.

Expected
In steps 1. and 2. instead of showing "No transactions found" the app should display a loading indicator.

[AndyQus]

cool, I had already implemented that yesterday :)
#111

[AndyQus]

@sallymoc I created all the logic. Please test.

[sallymoc]

@AndyQus
When I load the transactions page I see the loading indicator but if I tap then "By Address" and go back to "The last x epochs" I do not see the loading indictor anymore and says "No transactions" found again even when they are,