[#2299] Create subnet audit entry when network is deleted

[#2299]  Create subnet audit entry when network is deleted

    Update subnets in shared-network BDEL trigger rather than
    relying on foreign key update action

new files:
    src/share/database/scripts/mysql/upgrade_013_to_014.sh.in
    src/share/database/scripts/pgsql/upgrade_011_to_012.sh.in

configure.ac
    added:
    src/share/database/scripts/mysql/upgrade_013_to_014.sh
    src/share/database/scripts/pgsql/upgrade_011_to_012.sh

src/bin/admin/tests/mysql_tests.sh.in
    added 13 to 14 checks
src/bin/admin/tests/pgsql_tests.sh.in
    added 11 to 12 checks

src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc
src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc
    enabled disabled tests

src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc
    GenericConfigBackendDHCPv4Test::getAllSharedNetworks4Test()
    - updated expected audit entry order

src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc
    GenericConfigBackendDHCPv6Test::getAllSharedNetworks6Test()
    - updated expected audit entry order

src/lib/mysql/mysql_constants.h
    Updated schema version to 14

src/lib/pgsql/pgsql_connection.h
    Updated schema version to 12

src/share/database/scripts/mysql/.gitignore
src/share/database/scripts/mysql/Makefile.am
    added upgrade_013_to_014.sh

src/share/database/scripts/mysql/dhcpdb_create.mysql
    subnet rows are now updated directly in shared-network
    BEFORE delete triggers (v4 and v6)

src/share/database/scripts/pgsql/Makefile.am
    added upgrade_011_to_012.sh

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    subnet rows are now updated directly in shared-network
    BEFORE delete triggers (v4 and v6)