Make project context optional

[eleftherioszisis]

Issue: #372

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Flag	Coverage Δ
pytest	97.44% <100.00%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
app/queries/common.py	98.18% <100.00%> (ø)
app/queries/entity.py	100.00% <100.00%> (ø)
app/service/admin.py	85.29% <ø> (ø)
app/service/analysis_notebook_environment.py	100.00% <ø> (ø)
app/service/analysis_notebook_execution.py	100.00% <ø> (ø)
app/service/analysis_notebook_result.py	100.00% <ø> (ø)
app/service/analysis_notebook_template.py	100.00% <ø> (ø)
app/service/asset.py	99.09% <100.00%> (ø)
app/service/brain_atlas.py	100.00% <ø> (ø)
app/service/brain_atlas_region.py	100.00% <ø> (ø)
... and 66 more

... and 1 file with indirect coverage changes

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