feat(ecocredit/core): UpdateProjectAdmin/Metadata Msg implementations

[technicallyty]

Description

• adds MsgUpdateProjectAdmin
• adds MsgUpdateProjectMetadata
• implements sdk.Msg for both

ref: #979

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Author Checklist

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• included the correct type prefix in the PR title
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• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
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Reviewers Checklist

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• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
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• reviewed state machine logic
• reviewed API design and naming
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• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #1009 (3e8d958) into master (2818838) will increase coverage by 0.00%.
The diff coverage is 62.50%.

@@           Coverage Diff           @@
##           master    #1009   +/-   ##
=======================================
  Coverage   60.07%   60.08%           
=======================================
  Files         213      217    +4     
  Lines       23180    23212   +32     
=======================================
+ Hits        13926    13946   +20     
- Misses       7958     7971   +13     
+ Partials     1296     1295    -1     

Flag	Coverage Δ
experimental-codecov	59.98% <62.50%> (+<0.01%)	⬆️
stable-codecov	53.77% <62.50%> (+0.03%)	⬆️

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[ryanchristo]

Looks good to me. A couple minor suggestions. Pre-approving.

[aleem1314]

lgtm