Add new healthcheck for Local Links Manager

[callumknights]

Added so continuous deployment can be enabled for
Local Links Manager.

Trello: https://trello.com/c/uAx6eKAQ/2276-activate-continuous-deployment-for-local-links-manager

Testing

You should manually test your PR before merging.

This app doesn't have CI setup, and it would be misleading to do so:
the behaviour of the tests changes depending on the environment they
are run in. You should manually test in applicable environments,
until you are confident your change is not a breaking one.

Example steps to test in Integration:

• Click "Configure" for the Smokey job
• Change the "Branch specifier" to the name of your branch
• Run a new build of the Smokey project and check the results

Deployment

You need to manually deploy your PR after merging.

Steps to deploy a change:

• Run the Smokey deploy job to deploy the continuous Smokey loop
• Repeat this in Staging and Production

The manual Smokey job will pick up changes on master automatically. You only need to do a manual deployment for the continuous Smokey loop.

[thomasleese]

I think we need to add @app-local-links-manager to this:

smokey/features/publishing_tools.feature

Lines 47 to 53 in 1efb2db

	Scenario: Can log in to local-links-manager
	When I go to the "local-links-manager" landing page
	And I try to login as a user
	And I go to the "local-links-manager" landing page
	Then I should see "Local Links Manager"
	And I should see "Sign out"
	And I should see "Council"

[thomasleese]

Looks good, just got one comment!

[MuriloDalRi]

What @thomasleese said