add hexagon aggregation example

[oriolbx]

Add Leaflet and Gmaps example of point aggregation with hexagon aggregation

[ivanmalagon]

If you want these example to show up in the developer center, you must write them in examples.json.

If not, let me know.

[oriolbx]

done @ivanmalagon :)

[inigomedina]

@oriolbx, as a common rule of styling, for a better understanding, add comments to each code block so that users can easily understand them.

[oriolbx]

Ok, this is not on the rest of examples, that means that we would need to modify all existing examples with comments for each block of code, right?

[ivanmalagon]

I've merged this PR but it won't be published to docs until another PR with code gets merged.

We did a change to avoid differences between docs and code and we need to publish a tag in order to reflect changes in docs.

Since we're in active development of v4.1 this isn't a problem. We're going to merge code these days.

[oriolbx]

Great! Thanks for the info! :)