#### What type of PR is this?
/kind feature
/kind api-change
/area core
/milestone 2.0
#### What this PR does / why we need it:
Add an endpoint to grant permissions to user.
#### Which issue(s) this PR fixes:
Fixes #
#### Special notes for your reviewer:
Test steps:
1. Start Halo
2. Check the initial password in the console log
3. Request <http://localhost:8090/webjars/swagger-ui/index.html> from browser and you will be redirected to login page
4. Input the username(admin) and the password you got just now
5. Grant permission as you wish
#### Does this PR introduce a user-facing change?
```release-note
None
```
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#### What type of PR is this?
/kind feature
/area core
/milestone 2.0
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#### What this PR does / why we need it:
新增插件设置，允许通过 Setting 自定义模型生成表单并收集其值为 ConfigMap
插件可以通过注入 SettingFetcher 来获取值并使用它,例如：
```java
Sns sns = settingFetcher.getGroupForObject("sns", Sns.class);
```
#### Which issue(s) this PR fixes:
<!--
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用法：`Fixes #<issue 号>`，或者 `Fixes (粘贴 issue 完整链接)`
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Fixes #
#### Special notes for your reviewer:
/cc @halo-dev/sig-halo
#### Does this PR introduce a user-facing change?
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```release-note
None
```
Ryan Wang