api: Add go files

I know this is a huge commit, but I can't be bothered to check
this in part by part.

api/domain_moderator_delete.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"net/http"
+)
+
+func domainModeratorDelete(domain string, email string) error {
+	if domain == "" || email == "" {
+		return errorMissingConfig
+	}
+
+	statement := `
+		DELETE FROM moderators
+		WHERE domain=$1 AND email=$2;
+	`
+	_, err := db.Exec(statement, domain, email)
+	if err != nil {
+		logger.Errorf("cannot delete moderator: %v", err)
+		return errorInternal
+	}
+
+	return nil
+}
+
+func domainModeratorDeleteHandler(w http.ResponseWriter, r *http.Request) {
+	type request struct {
+		Session *string `json:"session"`
+		Domain  *string `json:"domain"`
+		Email   *string `json:"email"`
+	}
+
+	var x request
+	if err := unmarshalBody(r, &x); err != nil {
+		writeBody(w, response{"success": false, "message": err.Error()})
+		return
+	}
+
+	o, err := ownerGetBySession(*x.Session)
+	if err != nil {
+		writeBody(w, response{"success": false, "message": err.Error()})
+		return
+	}
+
+	domain := stripDomain(*x.Domain)
+	authorised, err := domainOwnershipVerify(domain, o.Email)
+	if err != nil {
+		writeBody(w, response{"success": false, "message": err.Error()})
+		return
+	}
+
+	if !authorised {
+		writeBody(w, response{"success": false, "message": errorNotAuthorised.Error()})
+		return
+	}
+
+	if err = domainModeratorDelete(domain, *x.Email); err != nil {
+		writeBody(w, response{"success": false, "message": err.Error()})
+		return
+	}
+
+	writeBody(w, response{"success": true})
+}