[ADD] VoIP: DIDWW config

[jero-odoo]

New doc outlining basic configuration for DIDWW voip provider (both in the DIDWW system and in Odoo).

[robodoo]

[jero-odoo]

Hey @Felicious this is ready for review.
A few things to note:
-not sure about the "Enable phone.systems" heading. I do think this is worth its own section, but I am not sure the heading is the best.
-I added the screenshot with the plus sign because I wanted to make it clear, but I am ok with it being removed

• I was not sure about some of the parameters, so I based in on the screenshot. I do not know the why/how behind these options
  Like we discussed, I would like to do a follow up once we get this published because I would like to add some additional context if I can.
  Thanks!

[Felicious]

I think this should be a guilabel? Pushing this quick fix up as a commit (:

Suggested change

	Provider` field, select *DIDWW*. Finally, enter the :guilabel:`Voip Username` and :guilabel:`Voip
	Secret`, then save.
	Provider` field, select :guilabel:`DIDWW`. Finally, enter the :guilabel:`Voip Username` and :guilabel:`Voip
	Secret`, then save.

[Felicious]

Suggested change

	:alt: Add alt text.
	:alt: DIDWW provider, username, and secret credentials entered.

[Felicious]

@robodoo r+