Add IDs, filenames etc. to debug logging messages

[UniquePanda]

With #27 we added extensive debug logging capabilities.
However, the messages themselves only say what is happening but not for e.g. which ResumableFile.
They always add e.g. the relevant ResumableFile as an additional aprameter to the log call, but these objects are always collapsed in the dev console until you open them.
This means, if you are searching for messages that belong to the same file, chunk etc. you have to expand all of the collapsed objects, which is really annoying.

So, the messages themselves should include some kind of identifier (uniqueIdentifier, filename, chunk number etc.) which will make it easier to recognize them.
I think adding a function logIdentifier() or similar to every class makes sense, so that every message in that class is really using the same identifier.
The helper functions printDebugLow() and printDebugHigh() should then take an additional parameter (loggingIdentifier) and always add that to the message (maybe in the form of (<logIdentifier>) <messageText> to make sure the log identifiers are always in the same spot, regardless of the message length).