Review template for work items

[kimdhamilton]

Questions:

• Does this structure look generally agreeable?
• Do we have a sample minimal/"empty" spec to replace as a starting point?

Note that this is a fallback for when the other WG work item templates do not apply. Those are:

• https://github.com/decentralized-identity/template-for-registry-workitems
• https://github.com/decentralized-identity/template-for-profile-workitems
• https://github.com/decentralized-identity/template-IETF-bound

We will also need to ensure those are up-to-date