logic: indexer command refactoring

* moved SystemHeaderSearchPaths and FramewordSeearchPaths of indexer cxx indexer commands to CompilerFlags section
* added SourceGroupTestSuite to test indexer command generation of all source groups
* removed "compile_commands.json" from gitignore, because a resource file for the tests has this name

bin/test/data/SourceGroupTestSuite/cxx_cdb/input/compile_commands.json

@@ -0,0 +1,7 @@
+[
+	{
+		"directory": "src",
+		"command": "clang-tool -fms-extensions -fms-compatibility -fms-compatibility-version=19  -isystem '/include/path/from/cdb'  -D DEFINE_FROM_CDB=\"some_value\" -std=c++14  /FS  './Test.cpp'",
+		"file": "./Test.cpp"
+	}
+]

bin/test/data/SourceGroupTestSuite/cxx_cdb/input/src/Test.cpp

@@ -0,0 +1 @@
+.

bin/test/data/SourceGroupTestSuite/cxx_cdb/input/src/Test.h

@@ -0,0 +1 @@
+.