add gis examples

[wang-boyu]

For projectmesa/mesa-geo#128.

Moved the following examples into gis/ folder:

• https://github.com/projectmesa/mesa-geo/tree/main/examples
• https://github.com/wang-boyu/agents-and-networks-in-python

[rht]

The external data very likely requires an attribution. I think we can just write a script to download the data instead, and document in the readme.

[wang-boyu]

Good question. Let me figure this out.

[wang-boyu]

Changes made to this PR:

• Rebase to current main branch
• Update dependencies of Mesa-Geo to be ~=0.5.0
• Zip data files in the agents_and_networks example
• Update data licenses in the following examples to be CC BY-SA 4.0 as mentioned in the abmgis repo from where we got the data:
  • agents_and_networks
  • population
  • rainfall
  • urban_growth

Should be ready for review now.

[tpike3]

As discussed this is a big merge, but the license issue is resolved. So it would be prudent to merge and then deal with any issues as we get mesa-examples stood up.