feat(ZNTA-2379) test button grommet component

[ghost]

JIRA issue URL: https://zanata.atlassian.net/browse/ZNTA-2379

Task

• test Grommet with Typescript (webpack build)
• replace bootstrap button with grommet button on Languages page

Checklist

• JIRA link
• Check target branch
• Make sure all commit statuses are green or otherwise documented reasons to ignore
• QA needs to evaluate against the JIRA ticket
• Changed files and commits make sense for this PR

See Zanata Development Guidelines more for information.

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This change is 

[codecov]

Codecov Report

Merging #717 into master will increase coverage by 0.9%.
The diff coverage is 0%.

@@             Coverage Diff             @@
##             master     #717     +/-   ##
===========================================
+ Coverage     33.54%   34.45%   +0.9%     
- Complexity     5781     5900    +119     
===========================================
  Files          1580     1604     +24     
  Lines         63183    67459   +4276     
  Branches       7362     8455   +1093     
===========================================
+ Hits          21197    23240   +2043     
- Misses        40052    42244   +2192     
- Partials       1934     1975     +41

Impacted Files	Coverage Δ	Complexity Δ
...ata-frontend/src/app/containers/Languages/index.js	8.16% <0%> (+8.16%)	0 <0> (ø)	⬇️
...-frontend/src/app/editor/components/Pager/index.js	58.33% <0%> (-18.14%)	0% <0%> (ø)
...end/src/app/editor/reducers/header-data-reducer.js	90.9% <0%> (-9.1%)	0% <0%> (ø)
...erver/zanata-frontend/src/app/utils/StringUtils.js	37.5% <0%> (-6.95%)	0% <0%> (ø)
.../zanata-frontend/src/app/reducers/admin-reducer.js	83.33% <0%> (-4.55%)	0% <0%> (ø)
...ata-frontend/src/app/editor/reducers/ui-reducer.js	84.48% <0%> (-3.4%)	0% <0%> (ø)
...rc/app/editor/components/ActivityFeedItem/index.js	89.28% <0%> (-2.15%)	0% <0%> (ø)
...a/webtrans/server/rpc/AddReviewCommentHandler.java	96.07% <0%> (-1.29%)	14% <0%> (+4%)
...nd/src/app/editor/reducers/phrase-reducer/index.js	97.26% <0%> (-0.46%)	0% <0%> (ø)
...in/java/org/zanata/security/SecurityFunctions.java	3.57% <0%> (-0.28%)	9% <0%> (+4%)
... and 224 more

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[ghost]

Reopened as #748