Added CI script, updated dependencies, and fixed bugs

-Added CI yaml file for workflows
-Added `doctest` as dependency
-Added test target executable to CMakeLists.txt
-Renamed `bin` scripts to remove `gdpm*` prefix
-Updated `SQLite 3` dependency in CMakeLists.txt
-Implement basic unit testing in `tests/basic.cpp`
-Fixed issue with handling `fmt` strings

bin/lines.sh

@@ -0,0 +1,2 @@
+# Call this from project root
+wc -l include/*.hpp src/*.cpp