CondInputLoader: Allow for non-unique folder-names
While working on the calibration procedure for LAr SuperCells we discovered that the CondInputLoader implicitly assumes uniqueness of database-folders (the folder-string is used as map-key). This assumption doesn't always hold. In our case, we are reading the same folder from multiple SQLite-files in order to merge them. With this MR, the folderstring-key'ed map is removed, instead we linearly search the m_keyFolderMap. That's a bit slower but this happens only once per job in initialize.