Qt5 built in qwt (#570)

- qt4->qt5
- in built qt5 6.1.5 because rhel7 is not upto date with qt5, removed findqwt.cmake
- made a fix in qwt lib (qwt_plot_layout.h) to work with 5.15 and lower versions for qrect constr.
- qt5 forms fixed, qt4 many hard coding forms switched to forms including qtabwidget, scrolls etc, fonts moved to forms
 - docking option enabled by default, removed option to disable docking feature from "Mode"
- added qVersionResolve utility functions to handle compatibility before and after qt5.12
- qtplots (ian's code) takes in gain mode enable to set some settings within the class, with proper gain plot ticks
- ensure gain plots have no zooming of z axis in 2d and y axis in 1d
- removed placeholder text in qpalette in main window form as its not supportd until 5.12 (so using qt5.9 designer insted of qt5.15 to cope)
- tab order
Servers:
- fixed some error messages that were empty for fail in funcs (mostly minor as if this error, major issues)

slsDetectorGui/src/qTabDeveloper.cpp

@@ -279,15 +279,19 @@ void qTabDeveloper::Initialization() {
 void qTabDeveloper::PopulateDetectors() {
     LOG(logDEBUG) << "Populating detectors";
 
-    comboDetector->clear();
-    comboDetector->addItem("All");
-    auto res = det->getHostname();
-    if (det->size() > 1) {
-        for (auto &it : res) {
-            comboDetector->addItem(QString(it.c_str()));
+    try {
+        comboDetector->clear();
+        comboDetector->addItem("All");
+        auto res = det->getHostname();
+        if (det->size() > 1) {
+            for (auto &it : res) {
+                comboDetector->addItem(QString(it.c_str()));
+            }
         }
+        comboDetector->setCurrentIndex(0);
     }
-    comboDetector->setCurrentIndex(0);
+    CATCH_DISPLAY("Could not populate readouts for dacs/adcs",
+                  "qTabDeveloper::PopulateDetectors")
 }
 
 slsDetectorDefs::dacIndex