Refactor functions that include running isolated simulations [vcs: #minor]

[anilbey]

Description

RNGSettings is not Cell or Synapse dependent. It is NEURON dependent. This PR removes the RNGSettings dependency in Cell and Synapse. It also creates the IsolatedProcess to consistently handle the scenarios require running NEURON in isolation. Removing RNGSettings helps there since now there is one less parameter to pass to the subprocess.

Changes

• Decouple Cell from RNGSettings
• Decouple Synapse from RNGSettings
• Have a single way of isolating processes via IsolatedProcess
• Remove redundancies in tools.py
• Add missing unit tests for tools.py #76
• RNGSettings.get_instance() replaces constructor
• Remove tox-uv until https://github.com/astral-sh/uv/issues/2235 is fixed.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 93.24324% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 90.86%. Comparing base (eb63577) to head (b629e38).

Files	Patch %	Lines
bluecellulab/cell/core.py	61.90%	8 Missing :warning:
bluecellulab/synapse/synapse_types.py	62.50%	6 Missing :warning:
bluecellulab/utils.py	93.75%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #149 +/- ## ========================================== + Coverage 89.57% 90.86% +1.28% ========================================== Files 87 89 +2 Lines 5403 5320 -83 ========================================== - Hits 4840 4834 -6 + Misses 563 486 -77 ```

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