[BUG] CONFIG template hook is NOT idempotent.

[louwe]

[MANDATORY] Describe the bug [MANDATORY]
CONFIG template hook is NOT idempotent.

[MANDATORY] Bastille and FreeBSD version (paste bastille -v && freebsd-version -kru output)
0.10.20231125
14.0-RELEASE-p6
14.0-RELEASE-p6
14.0-RELEASE-p6

[MANDATORY] How did you install bastille? (port/pkg/git)
pkg

[optional] Steps to reproduce?

• Create a template with any CONFIG directive (ie. CONFIG set allow.mount;).
• Run the template more than once (ie. twice).

[optional] Expected behavior
The jail.conf file should only have 1 entry of allow.mount;, but it will have 2 entries instead.