Update optimizing-rotations with shift length info

[sysadmin1139]

• Adds headings for better demarcation.
• Defines 'secondary' with regards to tiers of on-call (do we need a glossary section?)
• Adds a couple points to the management section
• Adds new section on right-sizing shift lengths for a rotation to be more humane.

[alicegoldfuss]

This is extremely detailed and awesome! My one request: can you link to key phrase definitions the first time you mention them on the page? For example, you eventually define "Maximum response time" but until then I was wondering if a newcomer would understand what it was.

[alicegoldfuss]

I see the terms are split out more, which is great, but the initial reference still only looks like italicized words. Maybe GitHub isn't registering the link?

[sysadmin1139]

Okay! This should be more... usable.

[alicegoldfuss]

Thank you so much! Resolve the conflicts and I'll merge you on my next round!

[sysadmin1139]

Alrightie. Resolved those conflicts.