Web Perf services: Rename Sonā to siteboard + adjust description

[homj]

We changed our name from Sonā to siteboard (see https://getsona.io/en -> https://siteboard.io/en)

Also, siteboard is now more capable than ever, with two helpful new features:

1. DeepScans - full page scans of a website including subpages (based on the sitemap or crawled)
2. Monitoring - siteboard can monitor your website in regular intervals and lets you keep track of scores

I can open up a PR for this

[paulirish]

@homj go for it with the PR.