[Freeswitch-docs] Request for comment on new channel variable catalog

[Ryan Harris]

Hi list,

I've mostly completed "normalizing" the channel variables section.

On this page:
https://freeswitch.org/confluence/pages/viewpage.action?pageId=7766277

DTMF Variables and all pages below show the new catalog.

If there is _anything_ you think needs to be tweaked, please let me
know. Everything can be changed with relative ease: page ordering,
variable ordering, variable groups, formatting, datatypes, etc.

Here are some things to look for:

- check for correct data types -- we default to string when it's
ambiguous/don't know

- check for deprecated variables - I can mark them as such

- check for variables not marked as readonly - I can mark them as such