ari: Add application/x-www-form-urlencoded parameter support

ARI POST calls only accept parameters via the URL's query string.
While this works, it's atypical for HTTP API's in general, and
specifically frowned upon with RESTful API's.

This patch adds parsing for application/x-www-form-urlencoded request
bodies if they are sent in with the request. Any variables parsed this
way are prepended to the variable list supplied by the query string.

(closes issue ASTERISK-22743)
Review: https://reviewboard.asterisk.org/r/2986/
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Merged revisions 402555 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@402557 f38db490-d61c-443f-a65b-d21fe96a405b
ARI playback: Rename ARI Playback to Playbacks

Before playback was the only non plural resource.  It has been renamed to
playbacks for consistency.

(closes issue ASTERISK-22737)
Reported by: Paul Belanger
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Merged revisions 402560 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@402562 f38db490-d61c-443f-a65b-d21fe96a405b