Backport changes for Housekeeping Specs

See merge request gitlab-org/gitlab-ce!18595

fixed typos, added text for clarifiction; markdown.md

See merge request gitlab-org/gitlab-ce!19560

fixed broken links in index.md

See merge request gitlab-org/gitlab-ce!19559

Resolve "Upgrade Monaco editor and remove CopyWebpackPlugin"

Closes #44331

See merge request gitlab-org/gitlab-ce!17813

Set tooltips to have default boundary viewport

Closes #47518

See merge request gitlab-org/gitlab-ce!19561

Fix revealing a CI runner token doesn't actually reveal it

Closes #47552

See merge request gitlab-org/gitlab-ce!19567

Fix loading icon in activity view

Closes #47508

See merge request gitlab-org/gitlab-ce!19566

Fix markdown code highlighting in mr discussion

Closes #47521

See merge request gitlab-org/gitlab-ce!19564

Fix tasks completed header

Closes #47506

See merge request gitlab-org/gitlab-ce!19562

Update to GitLab Workhorse v4.3.1

See merge request gitlab-org/gitlab-ce!19525

Fix card title h3 headers

See merge request gitlab-org/gitlab-ce!19510

fix bug in call to monaco.Uri.  first param is checked with `typeof param === 'object'` which is true for `null` due to a JS quirk

Update NGINX error rate to a percentage

See merge request gitlab-org/gitlab-ce!19471

Backport of "Add assignee lists to boards"

See merge request gitlab-org/gitlab-ce!19464

QA: Redact credentials from URI in git output

Closes gitlab-qa#258

See merge request gitlab-org/gitlab-ce!19492

Use the default strings of timeago.js for timeago

Closes #47182

See merge request gitlab-org/gitlab-ce!19350

CE backport for the card class changes

See merge request gitlab-org/gitlab-ce!19453

Resolve "Labels were bold in 10.8 but not with bootstrap4"

Closes #47358

See merge request gitlab-org/gitlab-ce!19504

Override default font family hierarchy of bootstrap 4

Closes #47493

See merge request gitlab-org/gitlab-ce!19542