cleanup of source + build system

* seperated most parts into headers & source files
* seperated anthracite into libanthracite and anthracite-bin for modules
* built demo webAPI module
* rewrote some code to do things in the
* changed cmakelists to not build in src directory

src/file_main.cpp

@@ -0,0 +1,10 @@
+#include "./anthracite_main.hpp"
+#include "backends/file_backend.hpp"
+
+using namespace anthracite;
+
+int main(int argc, char** argv) {
+    auto args = std::span(argv, size_t(argc));
+    backends::file_backend fb(argc > 2 ? args[2] : "./www");
+    anthracite_main(argc, argv, fb);
+}