Add Heatmap layer support

[josx]

Signed-off-by: José Luis Di Biase [email protected] Fixes #88

Description

Create a new layer called Heatmap (ol/layer/Heatmap)

Motivation and Context

I need to show heatmap for disease in my country.

How Has This Been Tested?

I have replicated this openlayer example in App.vue, and tested running npm run dev

Screenshots (if appropriate):

Types of Changes

• [ ] Bug fix (non-breaking change that fixes an issue)
• [x] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.