Add id for Tasks and the depends_on attribute

[marchinho11]

Why?

• To build DAGs of tasks using Airflow or Dagster.
• Before loading an Attribute you should load a Hub (FK constraint)

What?

• Task ID
• Depends On

[codecov]

Codecov Report

Merging #12 (a79aa82) into main (5e4bf5a) will increase coverage by 0.12%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #12      +/-   ##
==========================================
+ Coverage   97.79%   97.92%   +0.12%     
==========================================
  Files          33       23      -10     
  Lines         909      963      +54     
==========================================
+ Hits          889      943      +54     
  Misses         20       20              

Impacted Files	Coverage Δ
hnhm/core/__init__.py	100.00% <ø> (ø)
hnhm/core/attribute.py	100.00% <100.00%> (ø)
hnhm/core/entity.py	100.00% <100.00%> (ø)
hnhm/core/group.py	100.00% <100.00%> (ø)
hnhm/core/migrations.py	100.00% <100.00%> (ø)
hnhm/core/priority.py	100.00% <100.00%> (ø)
hnhm/core/storage.py	100.00% <100.00%> (ø)
hnhm/core/tasks.py	100.00% <100.00%> (ø)
hnhm/file_storage.py	100.00% <100.00%> (ø)
hnhm/flow.py	95.95% <100.00%> (+0.30%)	⬆️
... and 6 more