feat: change default solver to idaklu

[martinjrobins]

Description

Fixes #4914

Note: as part of this change I've had to relax a lot of the test tolerances, due to the different default tolerances that we have for the IDAKLU solver. If users have existing code that uses the default solver and tolerances, this might fail suddenly when they upgrade. We have to think about how to handle this

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)

Key checklist:

• No style issues: $ pre-commit run (or $ nox -s pre-commit) (see CONTRIBUTING.md for how to set this up to run automatically when committing locally, in just two lines of code)
• All tests pass: $ python -m pytest (or $ nox -s tests)
• The documentation builds: $ python -m pytest --doctest-plus src (or $ nox -s doctests)

You can run integration tests, unit tests, and doctests together at once, using $ nox -s quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Attention: Patch coverage is 86.79245% with 7 lines in your changes missing coverage. Please review.

Project coverage is 98.66%. Comparing base (4ba8cd8) to head (b65abc3).

Files with missing lines	Patch %	Lines
src/pybamm/solvers/idaklu_solver.py	85.71%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4915      +/-   ##
===========================================
- Coverage    98.71%   98.66%   -0.06%     
===========================================
  Files          304      304              
  Lines        23478    23514      +36     
===========================================
+ Hits         23176    23199      +23     
- Misses         302      315      +13     

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