[FLORA-134] Render testedWith field in the package page

[tchoutri]

Proposed changes

• [x] TestedWith platforms are shown on the package page
• [ ] Only the first four are displayed, the rest is hidden.
• [ ] Display a "Show all…" link for the rest

Contributor checklist

• [x] My PR fixed #134
• [x] I have read and understood the CONTRIBUTING guide
• [ ] I have inserted my change and a link to this PR in the CHANGELOG