mirage/mirage: PR #1486: Remove some functions, also remove dependency on astring (replace code to use Stdlib String module)

@fc010c4

Stages:

• 🟠 x86_64-debian-10-4.13
• 🟠 arm64-debian-10-4.13

History:

• 13/11/2023 13:10 ✔️ @63f35bb (10m51s)
• 13/11/2023 13:08 🟠 @fc010c4
• 13/11/2023 13:01 🟠 @ceac4e6 (6m33s)
• 13/11/2023 12:57 🟠 @295fe8c (4m25s)
• 12/11/2023 20:15 🟠 @787d8b6