feat(backend): poc of concurrent subquery

[jdroenner]

Here is a brief summary of what I did:

[coveralls]

Coverage Report for CI Build 31974556214

Coverage decreased (-0.1%) to 87.609%

Details

• Coverage decreased (-0.1%) from the base build.
• Patch coverage: 5 uncovered changes across 4 files (110 of 115 lines covered, 95.65%).
• 158 coverage regressions across 6 files.

Uncovered Changes

File	Changed	Covered	%
geoengine/services/src/config.rs	2	0	0.0%
geoengine/operators/src/adapters/raster_subquery/raster_subquery_adapter.rs	83	82	98.8%
geoengine/operators/src/engine/query.rs	21	20	95.24%
geoengine/services/src/contexts/mod.rs	6	5	83.33%
Total (5 files)	115	110	95.65%

Coverage Regressions

158 previously-covered lines in 6 files lost coverage.

File	Lines Losing Coverage	Coverage
geoengine/services/src/datasets/external/edr.rs	146	76.38%
geoengine/datatypes/src/raster/util.rs	5	86.84%
geoengine/datatypes/src/raster/tiling.rs	3	95.47%
geoengine/operators/src/adapters/raster_subquery/raster_subquery_adapter.rs	2	89.23%
geoengine/services/src/config.rs	1	64.89%
geoengine/services/src/contexts/postgres.rs	1	97.25%

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Coverage Stats

Relevant Lines:	142578
Covered Lines:	124911
Line Coverage:	87.61%
Coverage Strength:	487616.14 hits per line

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💛 - Coveralls