fix!: use bigint for addCycles and getCyclesBalance

[ilbertt]

Uses BigInt for numbers that are actually supposed to be big integers according to the API.

Unfortunately, this fix required using a custom JSON parser and serializer, provided by the json-with-bigint package. Reimplementing it was not worth it. I've pinned the version of the package so that it minimizes the risk of introducing any vulnerabilities with future patches of the package.

Additionally, fixes #193.

[peterpeterparker]

JSON parser and serializer, provided by the json-with-bigint package.

Why not using @dfinity/utils JSON serializers?

[ilbertt]

Why not using @dfinity/utils JSON serializers?

@peterpeterparker the PocketIC API doesn't support parsing BigInt object format used by @dfinity/utils ({ "__bigint__": string }), it just expects plain numbers

[peterpeterparker]

Gotcha

[ilbertt]

@peterpeterparker when parsing a PocketIC server JSON response that contains a bigint, e.g. EncodedGetTimeResponse, we cannot use the jsonReviver from @dfinity/utils because that assumes the bigint field (in this case nanos_since_epoch) has shape { "__bigint__": string }, which is not the case for the PocketIC server API.
The nanos_since_epoch field is just a number.

[peterpeterparker]

Yeah took more time to understand the all PR and third party dependencies and not just the parsing. Thanks for the feedback.