mirage/mirage: PR #1509: Make Functoria become a sub-package of Mirage

@288267e

Stages:

• ❌ x86_64-debian-10-4.13 (2m18s)
• ❌ arm64-debian-10-4.13 (1m17s)

History:

• 14/03/2024 14:05 ✔️ @8d4b049 (7m50s)
• 14/03/2024 13:56 ❌ @288267e (2m18s)
• 14/03/2024 13:49 ❌ @9187cfb (3m54s)
• 13/03/2024 12:27 ✔️ @9cac811 (23m40s)
• 13/03/2024 12:14 ✔️ @96d07f2 (6m37s)
• 13/03/2024 12:13 🟠 @b8da876
• 13/03/2024 11:40 ✔️ @906332f (27m10s)
• 12/03/2024 16:18 ✔️ @f571856 (7h08m)
• 12/03/2024 14:44 ✔️ @313d602 (9m10s)
• 12/03/2024 14:29 🟠 @6809a13 (13m57s)
• 12/03/2024 14:29 🟠 @ee9e852
• 12/03/2024 14:21 ❌ @69e85cc (5m58s)
• 12/03/2024 14:21 🟠 @cd5889d