feat: parse all product assets in the stac rest server json response

[anesson-cs]

Fixes #346

The complete list of stac provider product assets (not only downloadLink and thumbnail) is parsed in the stac rest server json response.

[github-actions]

Test Results

       4 files  ±0         4 suites  ±0   4m 20s ⏱️ +34s
   388 tests +1     386 ✔️ +1    2 💤 ±0  0 ❌ ±0 
1 552 runs  +4  1 496 ✔️ +4  56 💤 ±0  0 ❌ ±0 

Results for commit d7ee7d7. ± Comparison against base commit bbd367a.

This pull request removes 1 and adds 2 tests. Note that renamed tests count towards both.

tests.units.test_stac_utils.TestStacUtils ‑ test_search_stac_items

tests.units.test_stac_utils.TestStacUtils ‑ test_search_stac_items_with_non_stac_providers
tests.units.test_stac_utils.TestStacUtils ‑ test_search_stac_items_with_stac_providers

♻️ This comment has been updated with latest results.

[github-actions]

File	Coverage
All files	89%	✅
eodag/rest/stac.py	80%	✅
tests/units/test_download_plugins.py	98%	✅

File	Coverage
All files	88%	✅
eodag/rest/stac.py	80%	✅
tests/units/test_download_plugins.py	98%	✅
eodag/rest/stac.py	80%	✅
tests/units/test_download_plugins.py	98%	✅

Minimum allowed coverage is 70%

Generated by 🐒 cobertura-action against 3c94009

[github-actions]

Code Coverage (Ubuntu)

File	Coverage
All files	82%	✅

Minimum allowed coverage is 70%

Generated by 🐒 cobertura-action against d7ee7d7

[github-actions]

Code Coverage (Windows)

File	Coverage
All files	77%	✅

Minimum allowed coverage is 70%

Generated by 🐒 cobertura-action against d7ee7d7