ACN: res_pjsip endpoint options

This commit adds the endpoint options required to control
Advanced Codec Negotiation.

incoming_offer_codec_prefs
outgoing_offer_codec_prefs
incoming_answer_codec_prefs
outgoing_answer_codec_prefs

The documentation may need tweaking and some additional edits
added, especially for the "answer" prefs.  That'll be handled
when things finalize.

This commit is safe to merge as it doens't alter any existing
functionality nor does it alter the previous codec negotiation
work which may now be obsolete.

Change-Id: I920ba925d7dd36430dfd2ebd9d82d23f123d0e11

contrib/ast-db-manage/config/versions/b80485ff4dd0_add_pjsip_endpoint_acn_options.py

@@ -0,0 +1,29 @@
+"""Add pjsip endpoint ACN options
+
+Revision ID: b80485ff4dd0
+Revises: fbb7766f17bc
+Create Date: 2020-07-06 08:29:53.974820
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'b80485ff4dd0'
+down_revision = '79290b511e4b'
+
+from alembic import op
+import sqlalchemy as sa
+
+max_value_length = 128
+
+def upgrade():
+    op.add_column('ps_endpoints', sa.Column('incoming_offer_codec_prefs', sa.String(max_value_length)))
+    op.add_column('ps_endpoints', sa.Column('outgoing_offer_codec_prefs', sa.String(max_value_length)))
+    op.add_column('ps_endpoints', sa.Column('incoming_answer_codec_prefs', sa.String(max_value_length)))
+    op.add_column('ps_endpoints', sa.Column('outgoing_answer_codec_prefs', sa.String(max_value_length)))
+
+
+def downgrade():
+    op.drop_column('ps_endpoints', 'incoming_offer_codecs_prefs')
+    op.drop_column('ps_endpoints', 'outgoing_offer_codecs_prefs')
+    op.drop_column('ps_endpoints', 'incoming_answer_codecs_prefs')
+    op.drop_column('ps_endpoints', 'outgoing_answer_codecs_prefs')