Add Eric Johnson's Office Hours Discussion on OKRs to the OKR handbook page

Why is this change being made?

I thought this was a great place to start adding more information on thinking about and approaching OKRs with very specific examples, and proactively addressing common questions. Great resource I thought the whole org could benefit from.

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what