ref(keyvaluedata): Change names and exports for better autocomplete

[leeandher]

Adds an explicit export to help with autocomplete (from a separate code review), and changes Group -> Container since the former has a meaning at Sentry.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.04%. Comparing base (070a2b3) to head (4d35624).
Report is 41 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #72939       +/-   ##
===========================================
- Coverage   88.20%   78.04%   -10.16%     
===========================================
  Files        2899     6604     +3705     
  Lines      180192   294433   +114241     
  Branches    32219    50763    +18544     
===========================================
+ Hits       158936   229789    +70853     
- Misses      15345    58307    +42962     
- Partials     5911     6337      +426     

Files	Coverage Δ
...tic/app/components/events/contexts/contextCard.tsx	76.19% <100.00%> (ø)
.../components/events/contexts/contextDataSection.tsx	100.00% <ø> (ø)
static/app/components/keyValueData/index.tsx	85.00% <100.00%> (ø)
...nce/newTraceDetails/traceDrawer/details/styles.tsx	51.93% <100.00%> (ø)

... and 3701 files with indirect coverage changes