Improve output lock

[maurerle]

This reduces the duration in which the output role takes the lock on the dataframes.
Eventually this helps to maintain the same speedup for simulations as the output role runs in a separate process.

[codecov]

Codecov Report

Attention: Patch coverage is 61.11111% with 7 lines in your changes missing coverage. Please review.

Project coverage is 76.61%. Comparing base (b9cf60e) to head (a48f2f7).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
assume/common/outputs.py	61.11%	7 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #496   +/-   ##
=======================================
  Coverage   76.61%   76.61%           
=======================================
  Files          50       50           
  Lines        6727     6727           
=======================================
  Hits         5154     5154           
  Misses       1573     1573           

Flag	Coverage Δ
pytest	76.61% <61.11%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests