Update the Validation rules to account for allowing `.`, `/`

[rhamzeh]

After #254

We'll need to do a follow-up of improving the validators:

• https://github.com/openfga/language/blob/main/pkg/js/validator/validate-rules.ts
• https://github.com/openfga/language/blob/main/pkg/go/validation/validation-rules.go
• https://github.com/openfga/language/blob/main/pkg/java/src/main/java/dev/openfga/language/validation/Validator.java

So that we can make use of these extra fields in the type in the CLI, VSCode and IntelliJ

Originally posted by @rhamzeh in #254 (comment)