Show detailed CPU load information in a tool-tip (#5970)

* Profiler rework

* Workaround for GCC bug

* Rollback QFile removal

* Use enum instead of a plain index to describe detailed stats

* Use the GCC workaround code for all compilers to avoid redundancy

* Update and fix comments

* Implement suggestions from review

* Split AudioEngine::renderNextBuffer() into separate functions, fix old formatting

* Remove QFile include

* Revert formatting changes

* Apply suggestion from review (remove unnecessary template parameter)

* Revert more formatting changes

* Convert DetailType to enum class

* DetailType enum class improvements suggested in review

* Use std::atomic for m_detailLoad

* RAII-style profiler probes

* Apply suggestions from code review

Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

* Fix namespace comment

* Improve CPU load widget precision and use floats for load computations

* Atomic m_cpuLoad

* Add custom step size support for CPULoadWidget

* Apply suggestions from review (convert the profiler probe into a nested class, other small changes)

* Do not limit stored load averages to 100%

---------

Co-authored-by: sakertooth <sakertooth@gmail.com>
Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

data/themes/classic/style.css

@@ -209,6 +209,7 @@ lmms--gui--Oscilloscope {
 lmms--gui--CPULoadWidget {
 	border: none;
 	background: url(resources:cpuload_bg.png);
+	qproperty-stepSize: 4;
 }
 
 /* scrollbar: trough */

data/themes/default/style.css

@@ -241,6 +241,7 @@ lmms--gui--Oscilloscope {
 lmms--gui--CPULoadWidget {
 	border: none;
 	background: url(resources:cpuload_bg.png);
+	qproperty-stepSize: 1;
 }
 
 /* scrollbar: trough */