feat(toolkit-lib): report hotswap messages into a message span

[mrgrain]

Requested by early toolkit-lib users, all hotswap messages are now reported into span. Structured data reported for start and end is intentionally limited and will be extended further in future.

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.81529% with 5 lines in your changes missing coverage. Please review.

Project coverage is 85.44%. Comparing base (ec93ebd) to head (e2832da).

Files with missing lines	Patch %	Lines
...ckages/aws-cdk/lib/api/deployments/deploy-stack.ts	92.30%	3 Missing ⚠️
...aws-cdk/lib/api/deployments/hotswap-deployments.ts	98.64%	0 Missing and 1 partial ⚠️
...ckages/aws-cdk/lib/api/hotswap/lambda-functions.ts	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #247      +/-   ##
==========================================
+ Coverage   85.27%   85.44%   +0.17%     
==========================================
  Files         212      212              
  Lines       36037    36123      +86     
  Branches     4561     4582      +21     
==========================================
+ Hits        30729    30865     +136     
+ Misses       5161     5105      -56     
- Partials      147      153       +6     

Flag	Coverage Δ
suite.unit	85.44% <96.81%> (+0.17%)	⬆️

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