Cargo.toml: Rename dist profile and add release-small

[oech3]

It seems --profile=dist is not used at anywhere and distributor might miss the profile name.

1. Rename dist profile to release.
2. Add codegen-units to the profile.
3. Add release-fast profile as other uutils projects do. Closes Add release-fast profile to Cargo.toml #582

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.88%. Comparing base (f73e575) to head (3e1f370).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #586   +/-   ##
=======================================
  Coverage   88.88%   88.88%           
=======================================
  Files          31       31           
  Lines        6300     6300           
  Branches      324      324           
=======================================
  Hits         5600     5600           
  Misses        578      578           
  Partials      122      122           

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[cakebaker]

Thanks!