This commit first moves the compose.validate() function out
with the functions that are needed by it. Then one by one
checked for which function is now not needed in compose.js.
This moves all validation related functions out of "compose.js"
to "compose_validate.js".
Splitting compose announce variables out of compose.js.
This commit moves the "user_acknowledged_all_everyone" and
"user_acknowledged_announce" out of compose.js to reduce
cyclic dependency of compose_validate on compose.js.
Moving wildcard mentions to compose_validate.
The wildcard mention settings are mostly used while validating.
Also to reduce the cyclic dependence of compose in
compose_validate, the related wildcard mentions are moved out to
compose_vaidate.js.
This also converts reset_acknowledged functions to set values
by passing values.
Anders Kaseorg
Priyam Seth
Priyank Patel