Switch to json

[F43nd1r]

It's hard to say that something this big is complete, but I can say that it is working. I compared the output of 4.9.1 and this. Results were similar with a few differences:

• Some Numbers are now Strings (and the other way around) because that is the type of the field they come from (types are no longer guessed but carried over from the source)
• Shared preferences keys are no longer split at dots (this is a wanted change)
• Some String arrays are now actually arrays ( "[x86, x86_64]" is now ["x86", "x86_64"])
• Due to the json limitation that a key is only saved with a value, device features are now assigned to true even in form mode (previously this was only the case in json mode)
• All not available fields now contain the standardized string "N/A", instead of just some of them.

Resolves #517.

Reports are saved as json (utf-8 encoded) instead of the custom format. I chose utf-8 because it is the java internal encoding and thus guarantees no problems with custom data and other user supplied strings.
Old reports will be converted by ReportConverter.
Legacy migration and conversion has been grouped in LegacyFileHandler.
JsonReportBuilder has been replaced with JsonUtils.

[F43nd1r]

@william-ferguson-au According to what I have tested, this is working now. However I do not want to merge this amount of change without confirmation. Is there something I should think of/check before merging this?

[william-ferguson-au]

I can't think of anything.
Merge it and we'll deal with the fallout (if there is any).