Fix Logger and other build issues (#7)

This branch fixes a couple of issues with the build
- stop linking everything in a library which is then linked against a single main. It doesn't work the way I wanted. If functionality needs to be exposed by a library, it can be done later or with a separate target
- This should also fix spdlog
- Source files are now in a separate meson file using mesons files() feautre
- Improve coverage generation by adding a script generating html coverage reports. This will hopefully keep the motivation higher to create more unit tests
- Increase the code coverage a bit to demonstrate that statement above is not a fluke 😄

Reviewed-on: #7

src/graphics/Bitmap.cpp

@@ -52,6 +52,11 @@ bool Bitmap<T>::setPixels(const std::vector<T>& pixels) {
     return true;
 }
 
+template <class T>
+std::vector<T> Bitmap<T>::getPixelsCpy() {
+    return mPixels;
+}
+
 template <class T>
 std::optional<std::vector<T>> Bitmap<T>::getLine(uint16_t line) {
     if (line >= mHeight) {

src/graphics/Bitmap.hpp

@@ -22,6 +22,7 @@
 #include <stdint.h>
 
 #include <cstdint>
+#include <memory>
 #include <optional>
 #include <vector>
 
@@ -41,6 +42,7 @@ class Bitmap {
     uint16_t getWidth();
     uint16_t getHeight();
     bool setPixels(const std::vector<T>& pixels);
+    std::vector<T> getPixelsCpy();
     std::optional<std::vector<T>> getLine(uint16_t line);
     std::optional<std::vector<T>> getCol(uint16_t col);