docs: add decision record about create/update timestamps

[paullatzelsperger]

What this PR changes/adds

Adds a decision record about how all or EDC entities will get a createTimestamp and an lastUpdateTimestamp.

Why it does that

Traceability, auditability.

Further notes

removed an unused method in DataRequest.java

Linked Issue(s)

Documents #1370

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 #1767 (da1058e) into main (2d4e898) will increase coverage by 0.13%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #1767      +/-   ##
==========================================
+ Coverage   67.63%   67.77%   +0.13%     
==========================================
  Files         792      795       +3     
  Lines       16933    16968      +35     
  Branches     1076     1079       +3     
==========================================
+ Hits        11453    11500      +47     
+ Misses       5017     5005      -12     
  Partials      463      463              

Impacted Files	Coverage Δ
...nnector/spi/types/domain/transfer/DataRequest.java	24.56% <0.00%> (+4.56%)	⬆️
...aceconnector/extension/jersey/JerseyExtension.java	100.00% <0.00%> (ø)
...tension/jersey/validation/ResourceInterceptor.java	91.66% <0.00%> (ø)
...jersey/validation/ResourceInterceptorProvider.java	100.00% <0.00%> (ø)
...n/jersey/validation/ResourceInterceptorBinder.java	100.00% <0.00%> (ø)
...negotiation/store/SqlContractNegotiationStore.java	87.93% <0.00%> (+0.06%)	⬆️
...econnector/extension/jersey/JerseyRestService.java	95.00% <0.00%> (+0.55%)	⬆️

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[ndr-brt]

One last typo, good to go for the rest