NeoVIM: enable better jsonnet language support

[dminca]

Want to experiment a bit with grafonnet library.

One main source of inspiration was mainly what you can achieve with jsonnet, for instance → https://gitlab.com/gitlab-com/runbooks/-/tree/master/metrics-catalog is a good example. Here they've created a global scope for SLI/SLO and Grafana dashboards out of them.

Luckily, NeoVIM is the most popular IDE which integrates jsonnet fairly easy

• a simple search on what you can achieve
• jsonnet language server integration for vim
• https://github.com/grafana/jsonnet-language-server
• https://github.com/google/vim-jsonnet
• https://grafana.github.io/grafonnet/index.html