feat(reaclib): working on building efficient reaclib tooling for general nuclear network

this commit primarily adds a more robust ability to cull reactions that are not needed from the generated header

assets/static/reaclib/meson.build

@@ -0,0 +1,13 @@
+required_headers = [
+    'reaclib.h',
+]
+
+foreach h : required_headers
+    if not cpp.has_header(h, include_directories: include_directories('include'))
+        error('SERiF requires the header file ' + h + ' to be present in the assets/static/reaclib/include directory.')
+    endif
+endforeach
+reaclib_reactions_dep = declare_dependency(
+    include_directories: include_directories('include'),
+)
+message('✅ SERiF reaclib_reactions dependency declared')

assets/static/reaclib/readme.md

@@ -0,0 +1 @@
+Use the utility `utils/reaclib/generateEmbeddedReaclibHeader.py` to generate reaclib.h