Update the observation date modeling that has been changed during the

[lmichel]

During the MANGO REC process, it has been suggested to simplify the representation of the observation dates (mango:EpochPostion.obsDate).
The mango:ObsDate complex type has been replaced with a simple attribute where the representation is given by its dmtype (<ATTRIBUTE dmrole="mango:EpochPosition.obsDate" dmtype="year" value="2000.0" \>).

This change requires the SkyCoord builder to be updated as well as the annotation builder.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.59%. Comparing base (f14fabb) to head (9522514).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #726      +/-   ##
==========================================
+ Coverage   79.54%   79.59%   +0.04%     
==========================================
  Files          91       91              
  Lines       10293    10294       +1     
==========================================
+ Hits         8188     8193       +5     
+ Misses       2105     2101       -4     

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[lmichel]

After the last comments in the MANGO data model RFC suggesting changes in the the observation date representation, this PR must be delayed until the new code support the final time representation in the model.

[bsipocz]

After the last comments in the MANGO data model RFC suggesting changes in the the observation date representation, this PR must be delayed until the new code support the final time representation in the model.

I'm changing it to a draft PR then, feel free to mark it back "ready for review" once it can be reviewed.