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

[CBenoit]

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.