Add REPORTDATA binding to AttestationProvider

[tuddman]

Adds get_attestation_report_with_data to the AttestationProvider trait so callers can bind a challenge (typically a nonce or a hash of a verifier-supplied transcript) into the TEE's REPORTDATA field. The default trait implementation returns Error::NotSupported, keeping the change purely additive for any existing downstream implementers.

LinuxTdxProvider overrides the new method: it accepts up to TDX_REPORT_DATA_LEN (64) bytes, zero-pads shorter inputs on the right, rejects oversized input with Error::NotSupported, and then forwards the buffer through the existing linux::get_tdreport_v15_kvm device path. The private get_tdreport helper is refactored to delegate to a new get_tdreport_with_data so all device interaction flows through a single point.

The tdx-attest quote CLI gains a -r/--report-data <hex> flag (optional 0x prefix) that routes to the new method when supplied.

Tests cover the new behavior:

• trait default returns NotSupported
• oversize (>64 byte) input is rejected
• short input (32-byte nonce) is accepted and zero-padded
• full-length (64-byte) input is accepted
• empty input behaves like the existing no-arg path

On non-TDX hosts the device-touching cases skip via the existing handle_expected_tdx_error helper.