Improvements for Broyden and Klement

[avik-pal]

See https://github.com/JuliaNLSolvers/NLsolve.jl/pull/287

Needs #297 to go in first

Fixes https://github.com/SciML/NonlinearSolve.jl/issues/260

Summary

1. Broyden and Klement can (re-)start with the true (inv-)jacobian if asked for
2. For Broyden, it improves robustness but makes Klement even more unstable for ill-conditioned problems
3. Klement with identity initialization makes the Jacobian always diagonal; the updated solver exploits this and is significantly faster
4. Klement for non-diagonal jacobians resets the jacobian if the jacobian is "too" ill-conditioned; this improves the stability somewhat
5. Bad Broyden Update Rule
6. Klement with true jacobian diagonal initialization
7. Initial Scaling factor to improve stability

TODOs

• [x] Diagonal Update Rule for Broyden
• [ ] ~Exciting Mixing Update Rule for Broyden~
• [x] Testing

[codecov[bot]]

Codecov Report

Attention: 44 lines in your changes are missing coverage. Please review.

Comparison is base (021901e) 88.01% compared to head (c4bde4d) 86.08%. Report is 2 commits behind head on master.

Files	Patch %	Lines
src/utils.jl	69.87%	25 Missing :warning:
src/broyden.jl	90.27%	7 Missing :warning:
src/klement.jl	91.25%	7 Missing :warning:
src/trace.jl	25.00%	3 Missing :warning:
src/NonlinearSolve.jl	33.33%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #303 +/- ## ========================================== - Coverage 88.01% 86.08% -1.94% ========================================== Files 21 21 Lines 1669 1825 +156 ========================================== + Hits 1469 1571 +102 - Misses 200 254 +54 ```

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[avik-pal]

This should be good as well!