Update charter given feedback in #2, #3, #6, #8, and #10.

[hober]

From #2, especially @travisleithead's comment:

• Add text to the charter describing the pre-deliverable proposal phase.
• Tweak example destinations (drop WebAppSec?)
• Rename "deliverable" to something less serious sounding

From #3:

• use the word incubation
• Refrain from calling things standards or specifications
• Define the lifecycles of proposals and deliverables
  • describe exit conditions for an incubation
  • for how / whether a proposal should be abandoned/dropped from the group
  • or how a proposal should complete incubation

[hober]

I've attempted to address a whole bunch of this feedback in 0d58d27:

• use the word "incubate" more places
• renamed "deliverable" to "work item"
• added section defining (pre-work item) proposals and their lifecycle
• defined the lifecycle of a work item
• dropped use of the words "standard" or "specification" when talking about work items

Left to do:

• adjust the examples of WGs that work might end up in (drop WebAppSec?)
• spell out some considerations for how to choose a WG to migrate a work item to

[hober]

Progress update:

in 66c8fec:

• added the TAG to the list of groups to coordinate with.
• Require TAG review of work items at some point during their lifecycle.
• Add examples of PING and TAG output that should be considered when working on proposals and work items.

in 43b6aeb and 5d4b6fe:

• Clarify lifecycle of proposals and work items

Still to do:

• describe / define the Chairs' role in focusing the group on particular proposals or work items

[TanviHacks]

Thanks for making these changes Tess! They look good to me.

[travisleithead]

This is definitely an improvement.

I can live with it. However the more chill and process-averse part of me thinks the whole Proposals vs. Work Items and formal Acceptance bit is just over-the-top. If it were my CG (😎) I'd just have the chairs maintain a list of the "active" proposals, knowing that some things will go stale because an editor goes on parental leave or something. As the chairs shepherd the group forward they'd adjust the "active" list accordingly, and hear which proposals might want to consider graduating.

[hober]

Okay, I think this is a good batch of updates. I'd like to land it, once @erik-anderson approves. There is a bit of followup work; see #11.