This commit moves the deletion of copy constructor and copy assignment operators to the `mbed::interface::can` class, where both `mbed::CAN` and `mbed::interface::CAN` inherit enum types from. This allows `NonCopyable` to be removed from the inheritance list.

This commit adds provisions to enable using interface::CAN on targets that don't have DEVICE_CAN set to 1 (ie: they don't normally have a CAN peripheral).

This commit changes the `interface::can` namespace to a `struct`. This allows the enum types to be inherited and prevents breaking old code relying on referencing eg: `CAN::RxIrq`.

When enabled, the polymorphic CAN interface class inherits from this `interface::can` struct. If not enabled, the `mbed::CAN` class inherits from `interface::can` directly.

Co-authored-by: Vincent Coubard <vincent.coubard@arm.com>

Co-authored-by: Vincent Coubard (pan-) <Vincent.Coubard@arm.com>