Why this change?
This is a follow-up to 86b2e3aa3e.
Basically, we want to allow people to select more than 1 category as well.
What does this change do?
1. Change `type: category` to `type: categories` and support `min` and `max`
validations for `type: categories`.
2. Fix the `<SchemaThemeSetting::Types::Categories>` component to support the
`min` and `max` validations and switch it to use the `<CategorySelector>` component
instead of the `<CategoryChooser>` component which only supports selecting one category.
Why this change?
When editing a objects typed theme setting, the input fields which are
rendered should include a description so that the user knows the purpose
of the field which they are changing.
What does this change do?
This change adds support for adding description to each property in the
schema for an object by following a given convention in the locale file.
For a schema like this:
```
objects_setting:
type: objects
schema:
name: section
properties:
name:
type: string
required: true
links:
type: objects
schema:
name: link
properties:
name:
type: string
required: true
validations:
max_length: 20
url:
type: string
```
Description for each property in the object can be added like so:
```
en:
theme_metadata:
settings:
objects_setting:
description: <description> for the setting
schema:
properties:
name: <description for the name property>
links:
name: <description for the name property in link>
url: <description for the url property in link>
```
If the a description is not present, the input field will simply not
have an description.
Also note that a description for a theme setting can now be added like
so:
```
en:
theme_metadata:
settings:
some_other_setting: <This will be used as the description>
objects_setting:
description: <This will also be used as the description>
```
Why this change?
Prior to this change, there is no description being displayed for
objects typed theme setting because we were rendering a button instead
of the components for the various setting types which will render the
setting's description.
What does this change do?
1. Introduce `SiteSettings::Description` compoment to centralise the HTML
being rendered across all settings component.
2. Renders the `SiteSettings::Description` component after the edit
button in `site_setting.hbs`.
