mirage/mirage: PR #1607: Add support for the Unikraft backend targets

@35b6440

Stages:

• ❌ x86_64-debian-10-4.14 (1m14s)
• ❌ arm64-debian-10-4.14 (1m00s)
• ❌ x86_64-debian-10-5.2 (1m01s)
• ❌ arm64-debian-10-5.2 (10s)

History:

• 02/07/2025 17:29 ❌ @35b6440 (1m14s)
• 02/07/2025 17:27 🟠 @56fcb97 (running for 38d22h)
• 02/07/2025 17:09 ❌ @ecb173a (8m47s)