Big integer numbers are stored incorrectly in json

[PiotrKorkus]

When storing one of the following numbers:

• i64::MIN
• i64::MAX
• u64::MAX
  with Rust KVS into json file, the values written to json are rounded.

e.g.
for i64::MAX we are trying to store 9223372036854775807, however 9223372036854776000 is saved in json file.

Example tests can be found:
eclipse-score/reference_integration#72

[arkjedrz]

All numbers in JavaScript and JSON are double-precision floating point numbers. This is not a bug, this is by design.
We can:

• Detect such cases and throw an error on occurrence (accepted range: <-(2^53-1); 2^53-1>).
• Add information to docs that numbers over certain safe limit might be misrepresented.
  • Can be unsafe and introduce bugs that are difficult to observe.
• Use non-standard implementation of JSON handling.
• Use other data format.

References:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number
• https://json-schema.org/understanding-json-schema/reference/type

@PiotrKorkus, @vinodreddy-g

[PiotrKorkus]

It is expected that Vector will open source their JSON library. If that happens soon, maybe we can wait to see if they have some solution already as it is said to be ASIL-D qualified.