Generic port type tags
This MR introduces generic tags to provide port type hints, instead of custom names per plugin. This also allows us to improve probing by skipping probing operations that wouldn't be needed for the tagged ports. E.g. if a port is tagged as "primary AT" we will explicitly ignore any QCDM probing; or if a port is tagged as "QCDM" we will explicitly ignore any AT probing. This allows to have a very fast probing phase for modems with known layouts, an also simplifies the grab_port() implementation in most plugins that needed udev tags for port type hints.