Implement Key/OwnedKey for cosmwasm_std types

[uint]

Closes #57

TODO:

• impls for cosmwasm_std::Uint* and cosmwasm_std::Int* types
• API docs
• (brownie points) a derive provided by storey that handles delegation
• test the derive somehow!
  • got to love how the coverage hides the fact this stuff is untested except for "it compiles" ;)

[codecov]

Codecov Report

Attention: Patch coverage is 96.00000% with 10 lines in your changes missing coverage. Please review.

Project coverage is 91.60%. Comparing base (358546a) to head (ab00228).
Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/cw-storey/src/containers/key_set.rs	91.26%	6 Missing and 3 partials ⚠️
packages/storey-macros/src/lib.rs	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
+ Coverage   90.00%   91.60%   +1.59%     
==========================================
  Files          14       19       +5     
  Lines        2002     2216     +214     
  Branches     2002     2216     +214     
==========================================
+ Hits         1802     2030     +228     
+ Misses        179      161      -18     
- Partials       21       25       +4     

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