res_pjsip_diversion: implement support for History-Info

Implemention of History-Info capable of interworking with Diversion
Header following RFC7544

ASTERISK-29027 #close

Change-Id: I2296369582d4b295c5ea1e60bec391dd1d318fa6

contrib/ast-db-manage/config/versions/e658c26033ca_create_history_info_flag.py

@@ -0,0 +1,38 @@
+"""create history info flag
+
+Revision ID: e658c26033ca
+Revises: 1ae0609b6646
+Create Date: 2020-08-13 10:53:21.032591
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'e658c26033ca'
+down_revision = '1ae0609b6646'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import ENUM
+
+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_endpoints', sa.Column('send_history_info', ast_bool_values))
+
+
+def downgrade():
+    if op.get_context().bind.dialect.name == 'mssql':
+        op.drop_constraint('ck_ps_endpoints_send_history_info_ast_bool_values','ps_endpoints')
+    op.drop_column('ps_endpoints', 'send_history_info')