feat(List): Convert list to TypeScript

[rebeccaalpert]

Converted to TypeScript.

Fixes #1994.

[patternfly-build]

PatternFly-React preview: https://1946-pr-patternfly-react-patternfly.surge.sh

[nicolethoen]

@rebeccaalpert can you also add integration tests for this component as outlined on this README?

[dlabaj]

Also add integration tests for ListVariant, List, ListProps, ListItem, and ListItemProps.

[seanforyou23]

Awesome work! Can we use git mv to rename the primary component files instead of deleting and recreating them? If we can do this, we'll retain the ability to trace the history of these modules going forward which is important for tracking down when certain changes were made, by who, and why. Looks like you've done this for may of the component files already, if we could give the same treatment for the others that would be great.

[codecov-io]

Codecov Report

Merging #1946 into master will decrease coverage by 0.03%.
The diff coverage is 81.25%.

@@            Coverage Diff             @@
##           master    #1946      +/-   ##
==========================================
- Coverage   81.84%   81.81%   -0.04%     
==========================================
  Files         628      629       +1     
  Lines        7112     7116       +4     
  Branches      236      240       +4     
==========================================
+ Hits         5821     5822       +1     
  Misses       1163     1163              
- Partials      128      131       +3

Flag	Coverage Δ
#patternfly3	84.88% <ø> (ø)	⬆️
#patternfly4	77.73% <81.25%> (-0.07%)	⬇️
#patternflymisc	95.68% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
.../react-core/src/components/LoginPage/LoginPage.tsx	63.63% <ø> (ø)	⬆️
...tternfly-4/react-core/src/components/List/index.ts	100% <100%> (ø)
...nfly-4/react-core/src/components/List/ListItem.tsx	50% <50%> (ø)
...tternfly-4/react-core/src/components/List/List.tsx	83.33% <83.33%> (ø)

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[rebeccaalpert]

Added demo and test. I also addressed @dlabaj's PR feedback. @seanforyou23, as noted on Slack, git mv doesn't seem to net a different outcome, so I'm leaving that as-is for now.

[tlabaj]

Looks great Rebecca.