add timens to default generated config.json

[akhilerm]

• add timens to generated config.json
• fix tests to account for timens present in default config.json

[AkihiroSuda]

Why?

[akhilerm]

Why?

So that the default generated config.json has all the supported namespaces. Also, as per the discussion here

[cyphar]

Ah, I forgot that the time namespace doesn't allow a container to do settimeofday -- you need to set the time namespace offset at the beginning to do anything useful. This means that a configuration with just a time namespace and no offset doesn't really do anything.

So that the default generated config.json has all the supported namespaces.

The default configuration doesn't include user namespaces, for similar reasons. There is a stronger argument for making user namespaces enabled by default but you can't do that in a generic way.

[kolyshkin]

I also think that time namespace is special and should not be enabled by default.

[akhilerm]

Closing the PR as the consensus is not to enable timens by default.