Epic: Add support for new endpoints and fields in the Soroban RPC SDK.

[Shaptic]

### Tasks
- [ ] #936
- [ ] https://github.com/stellar/js-stellar-sdk/issues/997
- [ ] https://github.com/stellar/js-stellar-sdk/issues/943
- [ ] https://github.com/stellar/js-stellar-sdk/issues/944
- [ ] https://github.com/stellar/js-stellar-sdk/issues/942
- [ ] https://github.com/stellar/js-stellar-sdk/issues/973
- [ ] https://github.com/stellar/js-stellar-sdk/issues/998