Add a custom field type - [6h-12h]

[rootux]

Description

As an project admin - we can set custom fields. Currently, they are only free text. (See image from editing a project to see the current state) - תאריך, שם ההתארגנות

We want to support adding custom field types - specifically "Multiple choice" (select) with known entries. Also we want to be able to later on filter by that custom field.

TLDR -

• Add custom field type
• We can set it to be “Multiple choice”
• Default is “Short Text”
• We can checkbox whether or not to filter by it

Show on front page - should be "Allow filtering" - Seting this to true should show this field under the filter area