Add a script that can add all clusters as datasources for central grafana

[GeorgianaElena]

This adds a script that updates the datasources of our central grafana (the 2i2c one) to encompass all authenticated prometheus instances of our clusters. It also adds more colors to the print_color function.

It can be ran every time we add a new cluster, or deploy the support chart for an existing one.

Note:

1. I've ran this successfully
2. The clusters that failed to be added for reasons that were expected were:

Ref: #328

[yuvipanda]

Minor style nits, but otherwise yay!

We should run this every time we create a new cluster, so let's add that to the docs? When else should this be run?

Thank you for working on this!

[GeorgianaElena]

Thanks for the feedback @yuvipanda 🚀 ! I believe I have addressed all the comments in the last few commits. Let me know what you think 👀

[yuvipanda]

Two minor comments, feel free to merge after that.

Thanks a lot @GeorgianaElena!

[choldgraf]

Just a few quick documentation notes on this, thanks so much @GeorgianaElena this looks really nice :-) I am excited to start using this central Grafana!!!

[GeorgianaElena]

Thanks everyone for the feedback ✨ I believe I have addressed all the comments and this is now ready to merge 🚀