chore: removed data-faker from all test code

[paullatzelsperger]

What this PR changes/adds

Removes the data-faker library from the code base, replacing all occurrences with either UUID.randomUuid().toString() or other test strings and random numbers.

Why it does that

The data faker has caused problems with test stability, and in addition, it offers little value, all the while increasing the library footprint.

Further notes

.

Linked Issue(s)

Closes #1851

Checklist

• added appropriate tests?
• performed checkstyle check locally?
• added/updated copyright headers?
• documented public classes/methods?
• added/updated relevant documentation?
• assigned appropriate label? (exclude from changelog with label no-changelog)
• formatted title correctly? (take a look at the CONTRIBUTING and styleguide for details)

[codecov-commenter]

Codecov Report

Merging #1854 (f3968f8) into main (efe29b3) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1854      +/-   ##
==========================================
- Coverage   62.50%   62.50%   -0.01%     
==========================================
  Files         781      781              
  Lines       16640    16640              
  Branches     1085     1085              
==========================================
- Hits        10401    10400       -1     
- Misses       5789     5790       +1     
  Partials      450      450              

Impacted Files	Coverage Δ
...iation/ProviderContractNegotiationManagerImpl.java	90.00% <0.00%> (-0.56%)	⬇️

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[ndr-brt]

Totally ok with the faker removal, I'm not too keen on moving the test private methods on top of the class, as this will make the tests less readable, if it's something done by an automatic tool (I guess so), better to make them not static as they do not need to be