refactor: put DataAddress as Asset field

[ndr-brt]

What this PR changes/adds

Put DataAddress as a field of Asset

Why it does that

At first they were kept separated because DataAddress was like "private data for asset", but now we have also privateProperties in Asset, so there aren't good reasons to keep them split. Doing this we'll end up with a way more clean api.

Further notes

• added a /v3/assets api endpoint that would avoid breaking changes, though the advice is to switch to the new api as soon as possible.
• cleaned up AssetIndex tests on both in memory and postgresql, likely they could broke in the cosmosdb, eventually I will take care of fixing them

Linked Issue(s)

Closes #3151

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[codecov-commenter]

Codecov Report

Patch coverage: 71.75% and project coverage change: +0.02 🎉

Comparison is base (33a22bc) 65.93% compared to head (86e62ee) 65.96%.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3244      +/-   ##
==========================================
+ Coverage   65.93%   65.96%   +0.02%     
==========================================
  Files         842      844       +2     
  Lines       16875    16954      +79     
  Branches      926      930       +4     
==========================================
+ Hits        11126    11183      +57     
- Misses       5380     5400      +20     
- Partials      369      371       +2     

Impacted Files	Coverage Δ
...or/api/management/asset/v2/AssetApiController.java	100.00% <ø> (ø)
...ement/asset/validation/AssetEntryDtoValidator.java	63.63% <ø> (-22.73%)	⬇️
.../connector/store/sql/assetindex/SqlAssetIndex.java	0.00% <0.00%> (ø)
...ql/assetindex/schema/BaseSqlDialectStatements.java	0.00% <0.00%> (ø)
...ain/java/org/eclipse/edc/spi/asset/AssetIndex.java	0.00% <0.00%> (ø)
.../org/eclipse/edc/spi/types/domain/asset/Asset.java	67.74% <40.00%> (-15.60%)	⬇️
...d/transformer/to/JsonObjectToAssetTransformer.java	83.33% <50.00%> (-4.91%)	⬇️
...pi/management/asset/validation/AssetValidator.java	80.00% <80.00%> (ø)
...efaults/storage/assetindex/InMemoryAssetIndex.java	94.80% <80.95%> (+0.13%)	⬆️
.../edc/connector/service/asset/AssetServiceImpl.java	97.61% <100.00%> (+0.05%)	⬆️
... and 3 more

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[paullatzelsperger]

Since we are not exposing raw Assets (and thus: DataAddresses) to the public, this change is good. It'll simplifies our management API.

However, since the DataAddress itself is only a wrapper around a Map (i.e. properties) with named accessors, we could perhaps take things one step further and simplify even more by completely collapsing DataAddress into Asset. In another PR though.