No Maps

[fanman2014]

Hi, no maps are being loaded into the session. Tried on various browsers and same issue. Please help.

[Troyhy]

I created this PR #444 to allow adding own Map tiler key. I created a account and copied the key from here https://cloud.maptiler.com/account/keys/

[Troyhy]

I added also possibility to change the Cesium ion resource id, check the PR #444