Add uptimer tcp availability config to bosh deploy tasks

What is this change about?

This PR to the cf-deployment-concourse-tasks updates the uptimer config writing process to include the TCP availability measurement changes introduced to uptimer in https://github.com/cloudfoundry/uptimer/pull/27. These changes allow consumers of cf-deployment-concourse-tasks to configure any of the three bosh-deploy tasks to measure TCP availability to an app on the foundation with uptimer during a deployment. This change also automatically calculates the TCP domain of a Toolsmiths env, if provided, instead of explicitly requiring the TCP domain to be configured at the concourse task param level.

These changes are useful for testing the availability of TCP when we are performing deployments that cause downtime to the TCP router.

Release consideration

Measuring TCP availability correctly also depends on an uptimer bugfix: https://github.com/cloudfoundry/uptimer/pull/41 That fix needs to be merged, a new version of uptimer created and then subsequently consumed by cf-deployment-concourse-tasks before a new release of cf-deployment-concourse-tasks can be created.

Please provide contextual information.

Please check all that apply for this PR:

[ ] introduces a new task
[X] changes an existing task
[ ] changes the Dockerfile
[ ] introduces a breaking change (other users will need to make manual changes when this is released)

Did you update the README as appropriate for this change?

[ ] YES
[X] N/A

I updated the comments in the concourse task yaml themselves.

How should this change be described in release notes?

Updates bosh deploy tasks' configuration to allow uptime measurement of TCP availability.

What is the level of urgency for publishing this change?

[X] Urgent - unblocks current or future work
[ ] Slightly Less than Urgent

Tag your pair, your PM, and/or team!

Github team:

Slack: CF #wg-app-runtime-platform or #tas-containers-and-connectivity

cloudfoundry / cf-deployment-concourse-tasks