Make env config driven file and pre-populate layers conditionally - Preparation for VEDA release

[sandrahoang686]

Summary:

• What did I do? This makes the TITILER_ENDPOINT & TITILER_STAC_ENDPOINT env config file driven. Also this only loads the pre-populated layers options if the env vars are linked to MAAP. This to help prepare for the VEDA release

NOTE: A .env file will need to exist now and code should be deployed with the env vars defined

• Why *** did I do it? (What was the motivation?)

• How *** can someone test or demo my changes?

  * When relevant, use screenshots to document**

Fixes or Addresses Issue #: [ticket number & link]

https://github.com/NASA-IMPACT/veda-analytics/issues/82#issuecomment-1687139940

Checklist before requesting a review:

• [ ] My code follows the guidelines of this project
• [ ] I performed a self-review of my code changes
• [ ] I have added my changes to the change log (HISTORY.rst)
• [ ] I have completed spell-checking, removed unnecessary print statements & commented-out code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] New and existing unit tests pass locally with my changes

[sandrahoang686]

@emmalu what the warning logs will look like

[emmalu]

@emmalu what the warning logs will look like

Any chance we can align the second os.environ( statement? We may also want to be more specific and suggest re-starting the notebook, running the code snippet in a cell of its own, and then creating the stac_ipyleaflet map object again.

And in the case of the STAC_CATALOG_OBJECT, we may want to be more clear about setting the object as this dictionary:

os.environ['STAC_CATALOG'] = {
    "name": "REPLACE WITH STAC CATALOG NAME FOR LABEL USE"
    "url": "REPLACE WITH STAC CATALOG URL"
}