Adjustments to store description and pickup list layout

Closes #898 (closed)

What does this MR do?

Modifies some CSS to better present store information and pickup list.

Notable changes include increasing the avatar size from 35 to 50.

Also (for test purposes) play around with warning indicators on the right of pickup slots:

Anyone with store-manager permissions will see

• green warning indicators for filled pickups
• orange warning indicators for non-filled pickups
• red warning indicators if that pickup is today
• no warning indicators if the pickup is in the past

Regular store team members will see:

• red warning indicators if a non-filled pickup is today
• no warning indicators for anything else

I would like some feedback from store managers if this helps them :)

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

Pretty confident actually, just frontend styling stuff. The dangerous parts (color variables) have been tested well. There is a CSS selector with !important to avoid complicated logic but it's scoped in a very specific way.

Links to related issues

Follow-up of sorts to !1406 (merged) where the store description layout was modified.

How to test

Check the store description, and the pickup list with some of the configurations described above (can manage yes/no, has empty pickups today / soon, etc)

Screenshots (if applicable)

Store description:

Pickup list:

Bonus: store manager view

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