Add SaaS Platforms section

Why is this change being made?

This change adds a new section, SaaS Platforms. This change is needed for a few key reasons:

1. Introduce a group for Project Horse which is under way and growing, so they have representation in our handbook and other pages. Since this reports up through Infastructure on the engineering side, it should have a new section.
2. Provide a home for future SaaS Platforms, for example a potential FedRAMP offering or Regions (depending on how they are designed and implemented)
3. Represent the work that the Reliability and Scalability teams do for our SaaS services, and provide a way to discover them and publish a direction/vision page as desired. (For now it uses the infrastructure handbook page)

Why SaaS Platforms

These groups build and operate SaaS platforms, which are delivered as a service. Since this is likely to get simplified in some situations to a single word, that word can be "platforms" which is still MECEFU.

Potential alternative if "platforms" is too overloaded, is "Cloud Services" or "SaaS Services". We would want to ensure however that people reference this team as "SaaS" and not "Services" as that would overlap with our professional services team.

Approvals

• Chief Product Officer - sfwgitlab
• VP of Product Management - adawar
• VP of Infrastructure - sloyd
• The Director of Product relevant to the stage group(s) - joshlambert
• The Director of Engineering relevant to the stage group(s) - marin
• CEO - sytse

FYI

• Chief Technology Officer - edjdev
• VP of Development - clefelhocz1
• Director of Quality Engineering - meks
• Engineering Productivity - gl-quality/eng-prod
• The Product Marketing Manager relevant to the stage group(s) - @williamchia