chan_pjsip: add allow_sending_180_after_183 option

added new global config option "allow_sending_180_after_183"
that if enabled will preserve 180 after a 183

ASTERISK-29842

Change-Id: I8a53f8c35595b6d16d8e86e241b5f110d92f3d18

contrib/ast-db-manage/config/versions/0bee61aa9425_allow_180_ringing_with_sdp.py

@@ -0,0 +1,36 @@
+"""allow_sending_180_after_183
+
+Revision ID: 0bee61aa9425
+Revises: 8f72185e437f
+Create Date: 2022-04-07 13:51:33.400664
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import ENUM
+
+# revision identifiers, used by Alembic.
+revision = '0bee61aa9425'
+down_revision = '8f72185e437f'
+AST_BOOL_NAME = 'ast_bool_values'
+# We'll just ignore the n/y and f/t abbreviations as Asterisk does not write
+# those aliases.
+AST_BOOL_VALUES = [ '0', '1',
+                    'off', 'on',
+                    'false', 'true',
+                    'no', 'yes' ]
+
+def upgrade():
+    ############################# Enums ##############################
+
+    # ast_bool_values has already been created, so use postgres enum object
+    # type to get around "already created" issue - works okay with mysql
+    ast_bool_values = ENUM(*AST_BOOL_VALUES, name=AST_BOOL_NAME, create_type=False)
+
+    op.add_column('ps_globals', sa.Column('allow_sending_180_after_183', ast_bool_values))
+
+
+def downgrade():
+    if op.get_context().bind.dialect.name == 'mssql':
+        op.drop_constraint('ck_ps_globals_allow_sending_180_after_183_ast_bool_values', 'ps_globals')
+    op.drop_column('ps_globals', 'allow_sending_180_after_183')