[DNS] Issues with 'az network dns zone update'

[jtuliani]

Issues with 'az network dns zone update':

• -h help text has two groups of parameters both under the same heading 'Generic Update Arguments'. These should be grouped into a single group, containing add/remove/set (Fixed [Help] Fix argument group ordering. #1015)
• Not clear how add/remove/set should be used. For example, how do I add, edit or remove ARM Tags using this command? Needs concrete examples. (Tracked by Generic Update Needs Better Documentation #1582)
• Supporting If-none-match is pointless, it's only useful when creating zones, and that should be done via 'az network dns zone create'. We should support the option to control create-if-not-exist there, not here. (PR Fix #1123: Update az network dns zone update #1300)

[JasonRShaver]

• remove if-none-match
• add examples

[jtuliani]

For zone update, please add example of ARM tag create/update/remove

[jtuliani]

For tags, we need examples covering:

• Removing all tags
• Adding a new tag (suggest using "dept=finance")
• Removing an existing tag, leaving other items in place (again, use "dept=finance")

[tjprescott]

Reopening since the PR only addressed part of this issue.

[tjprescott]

Points 1 and 3 have been fixed. Point 2 is a more general issue with generic update that does not pertain specially to DNS so it is being tracked as a separate issue.