kubernetes: Make CSI test suite timeouts configurable

What would you like to be added: Current external CSI tests expect that pods can start in 5 minutes. This startup includes dynamic provisioning (if WaitForFirstConsumer is enabled), scheduling, volume attach and mount.

The timeout is extended to 10 minutes for snapshot restore and cloning tests.

Both timeouts (and maybe others) are hardcoded in the code base now. They should be configurable.

Why is this needed:

This suite is to be used by 3rd party driver vendors to test their CSI drivers. Different storage drivers can be slower, especially when dynamically provisioning a volume.

cc @pohly @msau42 /sig storage