[UI] Update stake display to use large number nomenclature

[idiom-bytes]

Motivation

See screenshot below, in the "stake" column. Numbers are getting > 100,000 OCEAN and expected to rise further.

Therefore we should adjust the display of the "stake" numbers to use large number nomenclature.

• K - Thousand
• M - Million

Py implementation

pdr-backend's strutil.py has a python implementation prettyBigNum() plus unit tests. It could be readily adapted to JS. I strongly recommend writing the tests first, then working backwards, because implementation time will be faster and the final result will be more robust.

Screenshot - Status quo