refactor: make device type recognition code common for general use

refactor: make device type recognition code common for general use

Changes:

- move device type registration out of "type filter" (filter.c)
to a separate and new dev-type.[ch] for common use throughout the code

- the structure for keeping the major numbers detected for available
device types and available partitioning available is stored in
"dev_types" structure now

- move common partitioning detection code to dev-type.[ch] as well
together with other device-related functions bound to dev_types
(see dev-type.h for the interface)

The dev-type interface contains all common functions used to detect
subsystems/device types, signature/superblock recognition code,
type-specific device properties and other common device properties
(bound to dev_types), including partitioning support.

- add dev_types instance to cmd context as cmd->dev_types for common use

- use cmd->dev_types throughout as a central point for providing
information about device types