Wrapper to assign futures to the correct event loop

[elacuesta]

Closes #307

Tasks:

• implementation (I'm working on a callback decorator instead)
• tests
• docs

[codecov]

Codecov Report

❌ Patch coverage is 60.60606% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.21%. Comparing base (84ba393) to head (147db94).
⚠️ Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
scrapy_playwright/utils.py	60.86%	9 Missing ⚠️
scrapy_playwright/_utils.py	62.50%	3 Missing ⚠️
scrapy_playwright/handler.py	50.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (84ba393) and HEAD (147db94). Click for more details.

HEAD has 3 uploads less than BASE

Flag	BASE (84ba393)	HEAD (147db94)
	6	3

Additional details and impacted files

@@             Coverage Diff             @@
##              main     #308      +/-   ##
===========================================
- Coverage   100.00%   93.21%   -6.79%     
===========================================
  Files            6        7       +1     
  Lines          603      634      +31     
===========================================
- Hits           603      591      -12     
- Misses           0       43      +43     

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[elacuesta]

Fixed by #351, closing.