#### What type of PR is this?
/kind feature
/milestone 2.0
#### What this PR does / why we need it:
添加选择附件类型的 FormKit 输入框。
在 Vue 单组件中使用：
```vue
<script lang="ts" setup>
const logo = ref("")
</script>
<template>
<FormKit
v-model="logo"
label="Logo"
type="attachment"
validation="required"
/>
</template>
```
在 FormKit Schema 中使用（插件 / 主题设置表单定义）：
```yaml
- $formkit: attachment
name: logo
label: Logo
```
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/2558
#### Screenshots:
<img width="671" alt="image" src="https://user-images.githubusercontent.com/21301288/198980581-ba90ec32-f205-4d03-8546-3c93238298e7.png">
#### Special notes for your reviewer:
/cc @halo-dev/sig-halo-console
#### Does this PR introduce a user-facing change?
```release-note
添加选择附件类型的 FormKit 输入框。
```
Ryan Wang
