Extract MS-RDPEGDI drawing orders into `ironrdp-pdu-egdi`

EGDI drawing orders are a logically self-contained spec family with a bounded type surface inside `ironrdp-pdu`.

## Goal

Validate that the per-PDU-crate template scales beyond the pilot, and reduce `ironrdp-pdu` scope by one spec family.

## Scope

- Move EGDI drawing-order types → `crates/ironrdp-pdu-egdi/`.
- Update consumers (`ironrdp-session`, `ironrdp-connector`, drawing-order handlers).

## Acceptance

- `crates/ironrdp-pdu-egdi` builds and is consumed.
- `ironrdp-pdu` no longer carries EGDI surface.