Reveal cardinality and requiredness in field list

Problem/Motivation

On /admin/structure/types/manage/*/fields.
The list of fields should show some essential properties like cardinality and whether the field is required.

Why?
An overview of fields with cardinality and requiredness is useful in a number of situations:

• When comparing the list to a spec sheet (e.g. spreadsheet that was used for initial data modeling)
• When reviewing / testing a pull request that changes the field list.
• When planning a data export.
• When targeting the fields with code for theming or functional purposes.

How?
The typical way to do it would be to introduce columns for each property that should be exposed.
This would easily pollute and clutter the table.

Instead, add a single column with a list of the properties, possibly using icons or symbols to indicate cardinality and requiredness.
An explanation can be revealed on hover or click/tap.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes