Lunie: Show loading indicator in staking overview

[faboweb]

UI Version: 0.10.2

Description:

Loading staking info (staked atoms) takes a long time (45s). We cache the results to improve UX. Still we need to show an indicator, that Voyager is still loading the data from chain.

[faboweb]

Consider #1271

[jbibla]

i actually think for loading the staking overview (at 45s) we need to have an obtrusive loader and an apology message 🐌🏗

[faboweb]

while loading the first time. after that, it could be done unobtrusive don't you think?

[NodeGuy]

Please move issues out of the backlog when moving them into Scrumptious.

[fedekunze]

waiting for cosmos/cosmos-sdk#2249 to be merged so that we won't require the loader