Fix tooltips for new bootstrap-vue version.

Closes none)

What does this MR do?

fixes the tooltips again after upgrading bootstrap-vue.

How confident are you it won't break things if deployed?

I think I got all occurences. Should be tested.

Links to related issues

• https://yunity.slack.com/archives/C1T1ZM9A4/p1577726756118500?thread_ts=1577128685.051400&cid=C1T1ZM9A4
• #747 (closed)

How to test

1. Open the application
2. Hover over the icons.

Screenshots (if applicable)

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))
• Once your MR has been merged, you are responsible to update the #foodsharing-beta Slack channel about what has been changed here. They will test your work in different browsers, roles or other settings