chore: add a couple of conveniences for easily running Kargo API locally

[rbreeze]

Related to #1205

Run . ./hack/import-env.sh to import environment variables from .env.dev to your local shell

Run make start-api-local to start the API locally

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.13%. Comparing base (fbddc83) to head (746361c).
Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1738   +/-   ##
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  Coverage   44.13%   44.13%           
=======================================
  Files         207      207           
  Lines       13105    13105           
=======================================
  Hits         5784     5784           
  Misses       7078     7078           
  Partials      243      243           

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[jessesuen]

Is the .env.dev useful outside of start-api-local? If not, WDYT about creating a ./hack/start-api-local.sh which has all the envs in the same file (can be overridden from environment).

Then the Makefile target just runs that?