Remove yang

[valentinsulzer]

Description

Remove the Yang2017 model as the parameter set is incomplete and secret

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)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ flake8
• All tests pass: $ python run-tests.py --unit
• The documentation builds: $ cd docs and then $ make clean; make html

You can run all three at once, using $ python run-tests.py --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

Merging #1577 (7a99063) into develop (ef21abe) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #1577      +/-   ##
===========================================
- Coverage    97.84%   97.83%   -0.01%     
===========================================
  Files          329      323       -6     
  Lines        17987    17915      -72     
===========================================
- Hits         17599    17527      -72     
  Misses         388      388              

Impacted Files	Coverage Δ
pybamm/parameters/parameter_sets.py	100.00% <ø> (ø)
...models/full_battery_models/lithium_ion/Yang2017.py	100.00% <100.00%> (ø)

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[valentinsulzer]

For future ref if needed: commit 4a9d317 has most up-to-date Yang2017 parameters