feat: api key authentication (#291)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/internal/common/errors.go

@@ -231,3 +231,27 @@ func (e *OneTimeAccessDisabledError) Error() string {
 	return "One-time access is disabled"
 }
 func (e *OneTimeAccessDisabledError) HttpStatusCode() int { return http.StatusBadRequest }
+
+type InvalidAPIKeyError struct{}
+
+func (e *InvalidAPIKeyError) Error() string {
+	return "Invalid Api Key"
+}
+
+type NoAPIKeyProvidedError struct{}
+
+func (e *NoAPIKeyProvidedError) Error() string {
+	return "No API Key Provided"
+}
+
+type APIKeyNotFoundError struct{}
+
+func (e *APIKeyNotFoundError) Error() string {
+	return "API Key Not Found"
+}
+
+type APIKeyExpirationDateError struct{}
+
+func (e *APIKeyExpirationDateError) Error() string {
+	return "API Key expiration time must be in the future"
+}