Treat environments matching `production/*` as Production for Cycle Analytics

Closes #24139

See merge request !8500

Resolve "Add link to Branches page help text?"

Closes #26129

See merge request !8377

Pipelines Vue

See merge request !7196

Validate label's title length

See merge request !5767

Update the gitlab-markup gem to the version `1.5.1`

See merge request !8509

Remove the project_authorizations.id column

See merge request !8479

Change CI template linter textarea with Ace Editor

Closes #24179 and #19701

See merge request !8452

Use #parts instead of #part to read all the parts of the Message.

Closes #26463

See merge request !8507

Make play button on Pipelines page accessible via keyboard

See merge request !8496

Resolve "Certain buttons are not accessible via the keyboard (Web)"

Closes #26238

See merge request !8469

View spec for Ryancharris/gitlab milestone counter number with delimiter

See merge request !8482

Made download artifacts button accessible via keyboard

Closes #26446

See merge request !8493

Looks like I was accidentally using #part which was adding an extra
empty Mime section

Fix Double Spaced CI Log

Closes #19086

See merge request !8349

For Cycle Analytics, the environment `production` is treated as a
special case, and used to update the `first_deployed_to_production_at`
metric.

With the Review Apps changes, slash syntax is used to group related
environments in the list. This is mostly used for `review/<branch>`
environments, but it's possible for people to have multiple production
environments, and someone might then want to group them like
`production/eu`, `production/us`, or even just make it look prettier
with `production/www.example.com`. In any of these cases, the first
deploy to one of these `production/*` environments now is treated as a
Production deploy.

Make successful pipeline emails off for watchers

Closes #24845

See merge request !8176

Log LDAP blocking/unblocking events to application log

See merge request !8042

Don't instrument 405 Grape calls

Closes #26051

See merge request !8445

Added update guides for 8.16RC1

See merge request !8502

+ add test for label.title length validation

Re-order update steps in the 8.14 -> 8.15 upgrade guide

Closes #26014

See merge request !8287

Record and show last used date of SSH Keys

See merge request !8113

Fix broken url on group avatar

Closes #26452

See merge request !8464

Fixes #26051.
Signed-off-by: Rémy Coutable <remy@rymai.me>

1. Gems need to be installed before we can run the
  gitlab:workhorse:install task
1. Update gitlab-shell after gitlab-workhorse since it's a manual step
  that needs to be done in `/home/git/gitlab-shell`
Signed-off-by: Rémy Coutable <remy@rymai.me>

Addresses: Issue #13810

1. Adds a last_used_at attribute to the Key table/model
2. Update a key's last_used_at whenever it gets used
3. Display how long ago an ssh key was last used