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/sysrepo_access.cpp b/src/sysrepo_access.cpp
index 16dfab5..2c80c2d 100644
--- a/src/sysrepo_access.cpp
+++ b/src/sysrepo_access.cpp
@@ -14,10 +14,22 @@
 {
     using namespace std::string_literals;
     switch (value->type()) {
+    case SR_INT8_T:
+        return value->data()->get_int8();
+    case SR_UINT8_T:
+        return value->data()->get_uint8();
+    case SR_INT16_T:
+        return value->data()->get_int16();
+    case SR_UINT16_T:
+        return value->data()->get_uint16();
     case SR_INT32_T:
         return value->data()->get_int32();
     case SR_UINT32_T:
         return value->data()->get_uint32();
+    case SR_INT64_T:
+        return value->data()->get_int64();
+    case SR_UINT64_T:
+        return value->data()->get_uint64();
     case SR_BOOL_T:
         return value->data()->get_bool();
     case SR_STRING_T: