build system and module refactoring + simple histogram scratch (#20)

* scratch adding histogram to image views

Histograms should come from some sort of histogram service. This is
currently just a POC.

* custom logger implementation w/o spdlog

* missing cmake file

* fix tests

* use operator<< over direct stream exposure

* rm print header

* add threading test + refactor towards interface libraries

omits the need for =target_include_directories= calls /everywhere/

* rm print header

* rm constexpr

* templated thread_pool

* fix doxyfile

* default enable doc building

* czi reader refactor

* rm erroneous include expression

* clang-format

* single lib include with PUBLIC visibility

* compile imgui stdlib

* clang format

* documentation update

centralize `LogLevelToString` to `ILog.hpp`

update docs and examples

lib/app/rendering/include/RenderHelpers.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "imgui.h"
+
+namespace pixelarium::application
+{
+bool dim_changed_p(const ImVec2& ref_rect, const ImVec2& new_rect);
+
+ImVec2 aspect_const_dimensions(const ImVec2& raw_dim, const ImVec2& curr_dim);
+};  // namespace pixelarium::application