Construct tasks with stac

[emmaai]

As the tile.

• take s3 paths and product names as input to construct task
• enable mixed inputs of s3 paths and product names
• fuse datasets and products properly when the datasets are constructed from stac

relevant change: https://github.com/opendatacube/odc-stac/pull/152

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 85.71429% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 76.86%. Comparing base (0a4bf97) to head (6beccc9). Report is 6 commits behind head on develop.

Files	Patch %	Lines
odc/stats/tasks.py	81.66%	11 Missing :warning:
odc/stats/model.py	0.00%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #124 +/- ## =========================================== + Coverage 76.59% 76.86% +0.26% =========================================== Files 34 35 +1 Lines 3205 3285 +80 =========================================== + Hits 2455 2525 +70 - Misses 750 760 +10 ```

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