improvement: add new ARGILLA_DATABASE_SQLITE_TIMEOUT environment variable setting

[jfcalvo]

Description

On the distribution task testing effort meeting we found some errors raised by SQLite when the database was locked because too many writes were executed concurrently.

Increasing the timeout for SQLite reduces this problem, specifically changing the connection timeout parameter from the default value of 5 seconds to 30 seconds make the problem totally disappear locally.

In this PR I have added a new ARGILLA_DATABASE_SQLITE_TIMEOUT environment variable that allow us to set a value for this. With a default value of 15 seconds.

The idea is to test this change on Spaces using a value of 30 seconds.

Refs #5000

Type of change

• Improvement (change adding some improvement to an existing functionality)

How Has This Been Tested

• Tested locally using SQLite and running 20 parallel response creations in bulk.

Checklist

• I added relevant documentation
• I followed the style guidelines of this project
• I did a self-review of my code
• I made corresponding changes to the documentation
• I confirm My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have added relevant notes to the CHANGELOG.md file (See https://keepachangelog.com/)

[codecov]

Codecov Report

Attention: Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 91.94%. Comparing base (cce4403) to head (f6b7972).

Files	Patch %	Lines
argilla-server/src/argilla_server/settings.py	83.33%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5213      +/-   ##
===========================================
- Coverage    91.96%   91.94%   -0.02%     
===========================================
  Files          135      135              
  Lines         5822     5835      +13     
===========================================
+ Hits          5354     5365      +11     
- Misses         468      470       +2     

Flag	Coverage Δ
argilla-server	91.94% <86.66%> (-0.02%)	⬇️

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