logic: Added SourceGroupCustomCommand to use with SourcetrailDB binaries

* Added new Source Group type SourceGroupCustomCommand to UI and ProjectSettings
* The Source Group executes a specified command on every source file
* The variables $SOURCE_PATH, $PROJECT_PATH, $DB_PATH, $STORAGE_VERSION can be passed
* The commands are executed after all other source groups finished indexing
* The command is executed with working directory set to project directory
* Errors during command execution are shown as status update and in the Status View
* SourceGroupCustomCommand cannot be partially cleared, when one file needs clearing the project must be fully re-indexed

src/lib_cxx/project/SourceGroupCxxCodeblocks.cpp

@@ -7,7 +7,6 @@
 #include "MessageStatus.h"
 #include "CodeblocksProject.h"
 #include "utility.h"
-#include "utilitySourceGroupCxx.h"
 #include "Application.h"
 
 SourceGroupCxxCodeblocks::SourceGroupCxxCodeblocks(std::shared_ptr<SourceGroupSettingsCxxCodeblocks> settings)
@@ -39,7 +38,7 @@ bool SourceGroupCxxCodeblocks::prepareIndexing()
 
 std::set<FilePath> SourceGroupCxxCodeblocks::filterToContainedFilePaths(const std::set<FilePath>& filePaths) const
 {
-	return utility::filterToContainedFilePaths(
+	return SourceGroup::filterToContainedFilePaths(
 		filePaths,
 		getAllSourceFilePaths(),
 		utility::toSet(m_settings->getIndexedHeaderPathsExpandedAndAbsolute()),