big-integer removal from the dependency tree

[klntsky]

Initially, we decided to use json-bigint fork adapted for our needs, because we knew that we depend on bignumber.js anyway. Since bigints package is deprecated, we are no more required to depend on bignumber.js, and so we should drop bignumber.js from all dependencies to avoid tech debt.

The ask:

1. Replace all uses of bignumber.js in the json-bigint package with native JS BigInt. Big integer type is only used for parsing/serializing there, it must be straightforward
2. Make sure the tests pass
3. Upload a new version to NPM or ask me to - https://www.npmjs.com/package/@mlabs-haskell/json-bigint
4. Update the version of json-bigint in aeson-bigint
5. Update the version of aeson-bigint in CTL

[klntsky]

This should be on top of #1521

[klntsky]

• Replace Data.BigInt with JS.BigInt #1551 removed indirect dep via aeson
• removed big-integer dependency as direct runtime dep for https://github.com/purescript-contrib/purescript-bigints

[klntsky]

It is also fairly easy to remove BigNumber.js and bignumber PS package dependency (used in Internal/Service/Blockfrost.purs)