Display Loading Spinner instead of Loading text

[gthoma17]

Business/User Value: As an explorer of Diem I want a more noticeable loading indicator so that I don't skim past it when it appears on the page in several places

Acceptance Criteria

GIVEN I navigate to a valid address
WHEN the data is loading
THEN a loading spinner is displayed instead of just text

DEV NOTES
[Relevant technical notes that developers may ask you to add to the story during weekly prep meeting (pre-IPM or IPM); sometimes they may add these themselves or add them as tasks]