Performances Improvement Ideas

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Hello,

I am a trainee at the MISL lab, and i've been assigned to try to find out how the performances of the Alvarium SDK can be improved.

I wrote a report that shows the benchmark results of the current Java SDK, and shows how the different optimisation ideas can reduce the alvarium's overhead.

There are some non-breaking changes that can be quickly implemented and improve the performances by 50%.

You can take a look at the report here :
Alvarium_Performances_Report.pdf

I wanted to submit two Pull Requests, the first one to implement the non-breaking changes, and a second one that would refactor many things, such as Annotators, the produced JSON format, signing process etc.

We can discuss about the breaking changes here before this monday meeting.

Thanks you !