In-memory sqlite locking & improved image handling

[guusw]

• Image ref-counting
• Loading RGB (no alpha) images directly into gfx::Texture
• Add in-memory locking mechanism for sqlite (on emscripten)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 73.83059% with 207 lines in your changes missing coverage. Please review.

Project coverage is 79.76%. Comparing base (7f4ceed) to head (98b1e59).

Files	Patch %	Lines
shards/modules/sqlite/sqlite.cpp	55.00%	72 Missing :warning:
shards/modules/imaging/imaging.cpp	84.83%	27 Missing :warning:
shards/core/serialization.hpp	0.00%	26 Missing :warning:
shards/modules/gfx/shader/translator.cpp	82.43%	13 Missing :warning:
include/shards/ops.hpp	0.00%	12 Missing :warning:
shards/modules/json/json.cpp	25.00%	12 Missing :warning:
shards/modules/core/flow.hpp	44.44%	10 Missing :warning:
shards/core/runtime.cpp	88.70%	7 Missing :warning:
shards/core/taskflow.cpp	66.66%	7 Missing :warning:
shards/modules/gfx/shader/translator.hpp	63.15%	7 Missing :warning:
... and 4 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## devel #1012 +/- ## ========================================== - Coverage 79.84% 79.76% -0.09% ========================================== Files 341 342 +1 Lines 54829 55125 +296 ========================================== + Hits 43779 43969 +190 - Misses 11050 11156 +106 ```

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