Deploy two Docker slaves PHP CD containers on Equatower

Summary:
IPs are currently ignored, as it requires Salt 2018.3.0 to set,
and Equatower is still a 2017.4.0 (February 26, 2018) version.

Test Plan:

• Declare them to Jenkins, configured with the private SSH key matching the public SSH key provided in authorized_keys
• Check https://cd.nasqueron.org/computer/: they're up
• Run a job: https://cd.nasqueron.org/blue/organizations/jenkins/tests-prod-environment-behaves-correctly/detail/master/1/pipeline

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1435