Make social options in footer settings more flexible

[mogmarsh]

Description

Instead of the hardcoded list of social options, we should have a repeater where the admin can specify whatever options they want, in whatever order they want, with whatever image file they want.
Each option should include:

• Name (used for alt text)
• URL
• Image file

The list should be sortable.

Use Case

Each user can decide which services to link to in their footer and which image files they want to use.

[mogmarsh]

should look into core social icons block as an option