feat: add initial implementation of osiris, the TLS terminator for Anubis

Signed-off-by: Xe Iaso <me@xeiaso.net>

cmd/osiris/internal/config/config.go

@@ -0,0 +1,31 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Toplevel struct {
+	Bind    Bind     `hcl:"bind,block"`
+	Domains []Domain `hcl:"domain,block"`
+}
+
+func (t *Toplevel) Valid() error {
+	var errs []error
+
+	if err := t.Bind.Valid(); err != nil {
+		errs = append(errs, fmt.Errorf("invalid bind block:\n%w", err))
+	}
+
+	for _, d := range t.Domains {
+		if err := d.Valid(); err != nil {
+			errs = append(errs, fmt.Errorf("when parsing domain %s: %w", d.Name, err))
+		}
+	}
+
+	if len(errs) != 0 {
+		return fmt.Errorf("invalid configuration file:\n%w", errors.Join(errs...))
+	}
+
+	return nil
+}