musiconhold: Add sort=randstart, and deprecate old stuff.

- adds sort=randstart (next to sort=, sort=random, sort=alpha)
- combines duplicate moh option parsing code into a single function
- adds deprecationwarnings for application=r to sort randomly
- adds deprecationwarnings for random=yes to sort randomly
- removes invisible code that was supposed to stay until 1.8 

The sort=randstart works like sort=alpha, except we start at a random
position.

Review: https://reviewboard.asterisk.org/r/3991/


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@423065 f38db490-d61c-443f-a65b-d21fe96a405b
chan_sip: Clarify that sipdebug=yes cannot be undone by the CLI.

Document it in sip.conf.

ASTERISK-24249 #close
Reported by: Avinash Mohod

Review: https://reviewboard.asterisk.org/r/3926/
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Merged revisions 423066 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 423067 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 423068 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 423069 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@423070 f38db490-d61c-443f-a65b-d21fe96a405b