Pagespeed Link with Pure CSS icon

[trieloff]

This is a riff on #555 and #554 with following changes:

1. the pagespeed icon is pure CSS, similar in minimalism to the exisiting icons
2. the display of the link is controlled through the pagespeed attribute

• feat(link-facet): enable pagespeed attribute to link to pagespeed insights
• feat(rum-explorer): add minimalistic, pure-css pagespeed icon

[aem-code-sync[bot]]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed. In case there are problems, just click a checkbox below to rerun the respective action.

• [ ] Re-run PSI checks
• [ ] Re-sync branch

Commits

* [84b12bd](https://github.com/adobe/helix-website/commit/84b12bd43342d64f66f3228549fd2c1af45af960) :white_check_mark: (latest) * [c9e33f9](https://github.com/adobe/helix-website/commit/c9e33f98f07466932834dcf6e2f2316c1bb31736) :white_check_mark: * [7b8edad](https://github.com/adobe/helix-website/commit/7b8edad2a8768a5912d693498d4b5bf6aabfa05d) :white_check_mark: * [c8dd6cf](https://github.com/adobe/helix-website/commit/c8dd6cfca011cd6898ab496c3e63a95d975ea1d8) :white_check_mark: * [7a40d0d](https://github.com/adobe/helix-website/commit/7a40d0d0c44e9239253b13846a90d64f34c65559) :white_check_mark: * [c4a355b](https://github.com/adobe/helix-website/commit/c4a355b50c641c1ca460376a6f9806c8344257ab) :white_check_mark:

[langswei]

Max will give you the same comment he gave me - wrap the URL in the querystring in encodeURIComponent() - otherwise looks good to me.