Geo: Fix Dynamic Backoff strategy and add specs

Closes #2639

See merge request !2128

[EE] Add a custom RSpec/SingleLineHook cop

See merge request !2036

Fix approval spec for project with only one member

See merge request !2117

Clean up Protected branches EE tests, removing unnecessary to_sym usage

Closes #2586

See merge request !2037

This cop adds an offense when `before`, `after`, or `around` are used as
single-line blocks.

[BE] Related Issues

See merge request !2091

Fix wrong link to codeclimate diff docs

See merge request !2125

Add docs for personal access tokens

See merge request !2127

Handle nil GeoNode to prevent spec failures

See merge request !2124

Suggest a way to resolve Geo tracking DB not having all the migrations

See merge request !2100

Merge branch 'sh-geo-add-migration-help-message' of gitlab.com:gitlab-org/gitlab-ee into sh-geo-add-migration-help-message

This will help customers resolve the problem on their own.

Also check for PostgreSQL earlier to fix spec.

Move License initializer to the front

See merge request !2121

[EE] Let PhantomJS load local images

Closes #2162

See merge request !2081

This reverts commit 8c838513.

Ignore CVE-2017-5029 in Nokogiri

Closes #33597

See merge request !12109

Ignore CVE-2017-5029 in Nokogiri

Closes #33597

See merge request !12109

[EE] Add an optional performance bar to view performance metrics

See merge request !2104

removes redundant project pull mirroring code from a bad merge

See merge request !2111

EE Version of 9-2-5 Master security update

See merge request !2094

Add explicit licensing for Elasticsearch

Closes #2581

See merge request !2108

This change fix a memory leak due to a Webkit bug:
https://github.com/ariya/phantomjs/issues/12903

Also:

- Whitelist only localhost and 127.0.0.1 in Capybara + JS specs
- Blacklist all requests to media such as images, videos, PDFs, CSVs etc.
- Log all the requests made.
Signed-off-by: Rémy Coutable <remy@rymai.me>