Soroban counter.sol example

[salaheldinsoliman]

This PR aims to make Solang support a simple counter.sol example on Soroban, where a storage variable is instatiated, modified and retrieved. The counter contract is only limited to uint64 data types, and only supports instance soroban storage.

This can be considered a "skeleton" for supporting more data and storage types, as well as more host function invokations.

• [x] Support Soroban storage function calls put_contract_data, get_contract_data and has_contract_data
• [x] Implement a wrapper init for storage_initializer
• [x] Implement wrappers for public functions
• [x] Insert decoding/encoding instructions into the wrapper functions
• [x] Soroban doesn't have function return codes. This needs to be handled all over emit
• [x] Add integration tests and MockVm tests

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 92.87671% with 26 lines in your changes missing coverage. Please review.

Project coverage is 88.58%. Comparing base (08dbe49) to head (1a8cb27).

Files	Patch %	Lines
src/linker/soroban_wasm.rs	80.00%	9 Missing :warning:
src/emit/soroban/mod.rs	93.00%	7 Missing :warning:
src/emit/instructions.rs	89.13%	5 Missing :warning:
src/emit/soroban/target.rs	93.02%	3 Missing :warning:
src/codegen/dispatch/soroban.rs	98.23%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1645 +/- ## ========================================== + Coverage 88.51% 88.58% +0.07% ========================================== Files 163 164 +1 Lines 72869 73152 +283 ========================================== + Hits 64497 64802 +305 + Misses 8372 8350 -22 ```

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