Moving some methods from threshold to utils

Two methods splitFileName and readFile seems to be more generic
and used not only by thresholds. Moving splitFileName and readFile
from the threshold namespace to utils.

Tested:
    Manual tests where done on CPUSensor. No differences detected
    comparing to results before these changes.

Signed-off-by: Zbigniew Kurzynski <zbigniew.kurzynski@intel.com>
Change-Id: I8ab58099eca740b6111a382f68f2ab32d7762a78
diff --git a/src/CPUSensor.cpp b/src/CPUSensor.cpp
index 6a803e2..801138a 100644
--- a/src/CPUSensor.cpp
+++ b/src/CPUSensor.cpp
@@ -53,7 +53,7 @@
     nameTcontrol += " CPU" + std::to_string(cpuId);
     if (show)
     {
-        if (auto fileParts = thresholds::splitFileName(path))
+        if (auto fileParts = splitFileName(path))
         {
             auto [type, nr, item] = *fileParts;
             std::string interfacePath;
@@ -129,7 +129,7 @@
             },
         };
 
-    if (auto fileParts = thresholds::splitFileName(path))
+    if (auto fileParts = splitFileName(path))
     {
         auto [fileType, fileNr, fileItem] = *fileParts;
         const auto mapIt = map.find(fileItem);
@@ -139,8 +139,8 @@
             {
                 auto [suffix, oldValue, dbusName] = vectorItem;
                 auto attrPath = boost::replace_all_copy(path, fileItem, suffix);
-                if (auto newVal = thresholds::readFile(
-                        attrPath, CPUSensor::sensorScaleFactor))
+                if (auto newVal =
+                        readFile(attrPath, CPUSensor::sensorScaleFactor))
                 {
                     genericUpdateValue(oldValue, *newVal, dbusName);
                 }