[OSSN-0088] Glance leaks resource types across namespaces

As a user of a project, I can see resource types associated to private namespaces I don't have access to:

╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ cat alicerc
export OS_CACERT=
export OS_PROJECT_NAME=separate
export OS_USERNAME=alice
export OS_PASSWORD=password
export OS_REGION_NAME=RegionOne
export OS_IDENTITY_API_VERSION=3
export OS_AUTH_TYPE=password
export OS_AUTH_URL=http://192.168.1.155/identity
export OS_USER_DOMAIN_ID=default
export OS_PROJECT_DOMAIN_ID=default
export OS_VOLUME_API_VERSION=3
╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ source alicerc
╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ glance md-namespace-list
+------------------------------------------+
| namespace |
+------------------------------------------+
| OS::Software::DBMS |
| CIM::ResourceAllocationSettingData |
| OS::Compute::CPUPinning |
| OS::Compute::Watchdog |
| OS::Compute::GuestMemoryBacking |
| OS::Compute::AggregateDiskFilter |
| OS::Compute::RandomNumberGenerator |
| OS::Compute::Hypervisor |
| OS::Compute::AggregateIoOpsFilter |
| OS::Compute::VirtCPUTopology |
| OS::Compute::HostCapabilities |
| CIM::ProcessorAllocationSettingData |
| OS::Compute::GuestShutdownBehavior |
| OS::Cinder::Volumetype |
| OS::Software::WebServers |
| OS::Compute::Libvirt |
| OS::Compute::XenAPI |
| OS::Compute::Quota |
| OS::Compute::VMwareFlavor |
| OS::Compute::VMwareQuotaFlavor |
| OS::Compute::InstanceData |
| OS::Compute::LibvirtImage |
| OS::Compute::AggregateNumInstancesFilter |
| OS::Glance::Signatures |
| CIM::VirtualSystemSettingData |
| CIM::StorageAllocationSettingData |
| OS::Software::Runtimes |
| OS::Compute::VMware |
+------------------------------------------+
╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ glance md-namespace-create alice-namespace
+------------+----------------------------------+
| Property | Value |
+------------+----------------------------------+
| created_at | 2021-02-25T15:55:55Z |
| namespace | alice-namespace |
| owner | 67f1495e5dc145abbfa7059c63c6eda2 |
| protected | False |
| schema | /v2/schemas/metadefs/namespace |
| updated_at | 2021-02-25T15:55:55Z |
| visibility | private |
+------------+----------------------------------+
╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ glance md-resource-type-associate --name alice-resource-type alice-namespace
+------------+----------------------+
| Property | Value |
+------------+----------------------+
| created_at | 2021-02-25T15:57:29Z |
| name | alice-resource-type |
| updated_at | 2021-02-25T15:57:29Z |
+------------+----------------------+

Now as a separate user

╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ source openrc demo demo
is_service_enabled:29: command not found: set +o xtrace
WARNING: setting legacy OS_TENANT_NAME to support cli tools.
╭─ubuntu@glance-devstack ~/devstack ‹master*›
╰─➤ $ glance md-resource-type-list
+---------------------+
| name |
+---------------------+
| OS::Glance::Image |
| OS::Cinder::Volume |
| OS::Nova::Server |
| OS::Nova::Aggregate |
| OS::Nova::Flavor |
| OS::Trove::Instance |
| bar |
| test |
| alice-resource-type |
+---------------------+