feat: final version of guess the number (#116)

* feat: final version of guess the number

Added:
- Errors
- XLM contract (had to make a work around since you can't unit test easily)
- Method to add funds
- More tests

It was very hard to test the auth mocking for the guessing so just skipped it for now.

A future improvement is to use an allowance and have the contract refill funds after a correct guess.

* fix: small tweaks to final guess contract

- Make both constants consistent as references
- Rename `reset_guess` to `reset_number`
- Add private readonly `number` getter

* fix: number shouldn't be public & make it return the number over option

* fix: revert to asset macro if not test

* fix: update guess component

* fix: unwrap error result

* feat: automatically deploy xlm if not on localnet

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Co-authored-by: Zach Fedor <zachfedor@gmail.com>

Author: willemneal