refactor: rust smart contract

[shreyasbhat0]

Closes #565 #578 #800

Checklist:

• [x] I have performed a self-review of my own code
• [x] I have documented my code in accordance with the documentation guidelines
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have run the unit tests
• [ ] I only have one commit (if not, squash them into one commit).
• [x] I have a descriptive commit message that adheres to the commit message guidelines

Please review the CONTRIBUTING.md file for detailed contributing guidelines.

[codecov[bot]]

Codecov Report

Merging #791 (c90827d) into main (3d4e684) will decrease coverage by 0.04%. The diff coverage is n/a.

:exclamation: Current head c90827d differs from pull request most recent head 2bb0d77. Consider uploading reports for the commit 2bb0d77 to get more accurate results

@@             Coverage Diff              @@
##               main     #791      +/-   ##
============================================
- Coverage     38.20%   38.15%   -0.05%     
  Complexity      801      801              
============================================
  Files           115      115              
  Lines         11161    11161              
  Branches        941      941              
============================================
- Hits           4264     4259       -5     
- Misses         6579     6584       +5     
  Partials        318      318              

Impacted Files	Coverage Δ
cmd/iconbridge/chain/bsc/receiver.go	57.80% <0.00%> (-1.22%)	:arrow_down: