feat(*): switched to spdlog for logging and organized headers (#1183)

* feat: updated PKGBUILD description
* feat: updated workflow syntax and dependencies
* feat: switched logging to spdlog
* chore: adjusted library defaults
* ci: fixed spdlog format string issues
* docs: fixed docs for libvideo2x functions
* feat: organized header files
* fix: fixed header installation directory
* feat: link spdlog statically if compiled from source
* feat: adjusted libvideo2x log level enum names
* feat: added version.h header

Signed-off-by: k4yt3x <i@k4yt3x.com>

include/libvideo2x/libplacebo.h

@@ -0,0 +1,22 @@
+#ifndef PLACEBO_H
+#define PLACEBO_H
+
+#include <filesystem>
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+#include <libavfilter/avfilter.h>
+}
+
+int init_libplacebo(
+    AVBufferRef *hw_ctx,
+    AVFilterGraph **filter_graph,
+    AVFilterContext **buffersrc_ctx,
+    AVFilterContext **buffersink_ctx,
+    AVCodecContext *dec_ctx,
+    int output_width,
+    int output_height,
+    const std::filesystem::path &shader_path
+);
+
+#endif  // PLACEBO_H