src,permission: add multiple allow-fs-* flags

[Ceres6]

Breaking change: Support for a single comma separates list for allow-fs-* flags is removed.

This means that

--alow-fs-read=/path/to/file.txt,/other/file/path.txt

Will be interpreted as a single file.

When using a single flag and including commas in said flag a warning will be emitted explaining the change.

Instead now multiple flags can be passed to allow multiple paths.

--allow-fs-read=/path/to/file.txt --allow-fs-read=/other/file/path.txt

Will allow access to both paths.

Fixes: nodejs/security-wg#1039