Create new page for partners

[xmnlab]

Create a new page for partners projects/organizations

the name of this page will be "Partners" and it should have its own menu: https://github.com/OpenScienceLabs/opensciencelabs.github.io/blob/main/conf.py#L70 it can be placed after "Teams"

the new page could be based on this other one: https://github.com/OpenScienceLabs/opensciencelabs.github.io/blob/main/pages/team.html

The projects that should be add for now are:

Alerta Dengue:

• https://info.dengue.mat.br/
• https://github.com/AlertaDengue/AlertaDengue

EpiGraphHub

• https://epigraphhub.org/
• https://github.com/thegraphnetwork/EpiGraphHub

ArxLang

• https://arxlang.org/
• https://github.com/arxlang/arx

[xmnlab]

done.