Connectivity modelling update

[erialC-P]

During our CEM release phase, we made some changes to the connectivity model that we didn't transfer into the intertidal repo. This PR commits those changes and makes a minor update to the mangrove shapefile source.
This PR:

• replaces the single year Global Mangrove Watch shapefile from the connectivity baseline class to now use the unioned GMW extent that we use with our DEA Mangroves product. To support this task, I created a flatgeobuf file of the unioned GMW shapefile and hosted it from our S3 dev bucket.
• adds code to import and add highest astronomical tide to the connectivity baseline class. This code is transferred directly from gdata1/projects/coastal/intertidal/Connectivity_testing_Robbi.ipynb. To support this task, I also added the CCBY 4.0 licensed HAT modelling from CSIRO onto our S3 dev bucket.

[github-actions]

For full integration test results, refer to the Tests directory README.

[robbibt]

Looks great @erialC-P! Ready to squash and merge