Add supplemental data sources (ECCC models)

[sjbruce]

ECCC-MSC has a number of models that can add value to the application in the form of WMS layers that should be able to be added with relatively low effort as additional layers.

https://eccc-msc.github.io/open-data/msc-data/readme_en/

Data layers such as wind speed, wave height, air temperature and storm surges are all relevant.