feat: expose AccessKey encode/decode api

[Gozala]

Summary

Fixes #294

This PR fixes/implements the following bugs/features

• Bug 1
• Bug 2
• Feature 1
• Feature 2
• Breaking changes

Adds ability to serialize access-key so it can be preserved across sessions

Test plan (required)

Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request changes UI.

Added a test to verify changes work

Closing issues

Fixes #294

After Merge

• Does this change invalidate any docs or tutorials? If so ensure the changes needed are either made or recorded
• Does this change require a release to be made? Is so please create and deploy the release

[codecov]

Codecov Report

Merging #296 (d67ddd0) into main (25c5215) will decrease coverage by 0.10%.
The diff coverage is 0.00%.

❗ Current head d67ddd0 differs from pull request most recent head 312cc0b. Consider uploading reports for the commit 312cc0b to get more accurate results

@@            Coverage Diff             @@
##             main     #296      +/-   ##
==========================================
- Coverage   61.47%   61.37%   -0.10%     
==========================================
  Files          40       40              
  Lines        2707     2711       +4     
  Branches      679      679              
==========================================
  Hits         1664     1664              
- Misses        571      575       +4     
  Partials      472      472              

Impacted Files	Coverage Δ
wnfs/src/private/keys/access.rs	47.05% <0.00%> (-6.28%)	⬇️

[matheus23]

Beat me to it! Thank you very much!