Update Elasticsearch guide

See merge request !1292

CE Upstream - Wednesday

Closes #1765

See merge request !1281

Remove deprecated upvotes and downvotes from the notes API

See merge request !1275

Re-compile merge request Vue app after jQuery ajax

Closes gitlab-ce#27134

See merge request !1264

Signed-off-by: Rémy Coutable <remy@rymai.me>

Add version requirements for Elasticsearch

See merge request !1291

[ci skip]

No more and/or in EE

See merge request !1284

Remove Pages readme

See merge request !1289

To prevent a redirect loop in docs.gitlab.com/ce/pages/

[ci skip]

Change Pages redirect

See merge request !1288

[ci skip]

# Conflicts:
#   doc/api/v3_to_v4.md

Add GitLab Pages guides

See merge request !1286

[ci skip]

Port of 28458-present-gitlab-version-for-v4-changes-on-docs

See merge request !1285

Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix admin email notification recipient group select list

Closes #1656

See merge request !1277

Present GitLab version for each V3 to V4 API change on
v3_to_v4.md. And add Merge Request link to the v3 to v4
documentation. Similar to changelog, mention the Merge Request id &
link for each change.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Chat slash commands show labels correctly

See merge request !1280

[Elasticsearch] More efficient search

See merge request !1282

[ci skip]

[ci skip]

Signed-off-by: Rémy Coutable <remy@rymai.me>

Backport "Change branch_name param to branch throughout V4 API"

See merge request !1276

# Conflicts:
#   doc/api/v3_to_v4.md