Implement int8, uint8, int16, uint16, int64, uint64 types

This sw did not support uint8 type, which is needed by the upcoming
driver CalibrationBox within cla-sysrepo, so we implemented uint8 and
other types in TODO sections.

Creating leaf_data_XXX_classes for all types would result in a lot of
redundant code so the base class was turned into a template and the type
is passed through the template argument.

Change-Id: I866a3933fe21ea7844299556e5aaf39b3e40e92f
Co-Authored-By: Jan Kundrát <jan.kundrat@cesnet.cz>
diff --git a/src/ast_values.hpp b/src/ast_values.hpp
index 350fc8d..44e98af 100644
--- a/src/ast_values.hpp
+++ b/src/ast_values.hpp
@@ -43,6 +43,12 @@
                                   identityRef_,
                                   double,
                                   bool,
+                                  int8_t,
+                                  uint8_t,
+                                  int16_t,
+                                  uint16_t,
                                   int32_t,
                                   uint32_t,
+                                  int64_t,
+                                  uint64_t,
                                   std::string>;