Installation/Update guides for 11.7

See merge request gitlab-org/gitlab-ce!24109

Add 11.7 CE to EE update guide

See merge request gitlab-org/gitlab-ee!8996

Remove redundant counts in snippets search

Closes #44353

See merge request gitlab-org/gitlab-ce!23952

Support new issue creation by email without subaddressing

Closes #29951

See merge request gitlab-org/gitlab-ce!23523

Support new issue creation by email without subaddressing for EE

See merge request gitlab-org/gitlab-ee!8806

[CE] Don't run checks for changed refs when specific changes are unknown

See merge request gitlab-org/gitlab-ce!23990

Don't run checks for changed refs when specific changes are unknown

See merge request gitlab-org/gitlab-ee!8800

Documentation: Make correction to URL, from https://about.gitab.com/handbook/documentation/...

See merge request gitlab-org/gitlab-ce!24137

Make correction to URL, from https://about.gitab.com/handbook/documentation/ to https://about.gitlab.com/handbook/documentation/ (I searched to see if this is a duplicate of an existing fix, didn't find one)

Geo: Improve non-Omnibus database documentation

Closes #8221

See merge request gitlab-org/gitlab-ee!8917

Update `include` parameter usage description

See merge request gitlab-org/gitlab-ce!24118

Update `include` parameter usage description

See merge request gitlab-org/gitlab-ee!8874

Clean up the GPG docs and mention push rules

Closes gitlab-ce#42363

See merge request gitlab-org/gitlab-ee!8975

Fix clone URL not showing if protocol is HTTPS

Closes #55896

See merge request gitlab-org/gitlab-ce!24131

Resolve "Add markdown editing buttons to the file editor"

Closes #27861

See merge request gitlab-org/gitlab-ce!23480

Add Knative metrics to Prometheus

See merge request gitlab-org/gitlab-ce!23972

Geo: Ignore invalid attributes when updating Geo node status

Closes #8966

See merge request gitlab-org/gitlab-ee!8957

GitLab 11.6.2 fixed the case for HTTP. However, HTTPS still did
not work because the protocol returned to `http_enabled?`
was the actual protocol in use (e.g. `https` instead of `http`).

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/55896

Geo: Fix metrics updates when secondary nodes are cached

Closes #9000

See merge request gitlab-org/gitlab-ee!8981

Refactor tracing settings

See merge request gitlab-org/gitlab-ee!8983

Added Comment to user avatar Image, Changed Fixtures to created ones, added shadow color

See merge request gitlab-org/gitlab-ce!23768

including verifying the project_slug

We now use `-issue` in order to support catch all email addresses

We now use `-merge-request` instead of `+merge-request+`
in order to support catch all email addresses

We now use `-unsubscribe` instead of `+unsubscribe`
in order to support catch all email addresses

targeting the service desk email handler

# Conflicts:
#	lib/gitlab/email/handler.rb