Fix sectionless items edge case

[santilococo]

This PR fixes an edge case bug introduced by #300.

The edge case is explained in #300 (comment)

The issue occurs because, for sectionless items (keys) to work, they must be at the top. However, the updated grafana template did not guarantee this unless the user explicitly placed them at the top of the grafana_ini variable. This approach is suboptimal, as the template should handle this automatically. This PR fixes the issue by managing this edge case first before processing other cases.

Example:

grafana_ini:
  security:
    admin_user: "admin"
  
  instance_name: "grafana.com"

With the previous PR, this would generate:

[security]
admin_user = admin
admin_email = admin@localhost

instance_name = grafana.com

This is incorrect, as instance_name becomes part of the security section and won't be recognized by grafana.

With this PR, the output is correctly generated as:

instance_name = grafana.com

[security]
admin_user = admin
admin_email = admin@localhost

[intermittentnrg]

Looking good!

[voidquark]

Nice find! 🚀