Remove unnecessary meta data on markdown files (#12)

Reviewed-on: https://gitea.com/gitea/docs/pulls/12

docs/development/api-usage.md

@@ -3,16 +3,8 @@ date: "2018-06-24:00:00+02:00"
 title: "API Usage"
 slug: "api-usage"
 sidebar_position: 40
-toc: false
-draft: false
 aliases:
   - /en-us/api-usage
-menu:
-  sidebar:
-    parent: "development"
-    name: "API Usage"
-    sidebar_position: 40
-    identifier: "api-usage"
 ---
 
 # API Usage

docs/development/hacking-on-gitea.md

@@ -3,16 +3,8 @@ date: "2016-12-01T16:00:00+02:00"
 title: "Hacking on Gitea"
 slug: "hacking-on-gitea"
 sidebar_position: 10
-toc: false
-draft: false
 aliases:
   - /en-us/hacking-on-gitea
-menu:
-  sidebar:
-    parent: "development"
-    name: "Hacking on Gitea"
-    sidebar_position: 10
-    identifier: "hacking-on-gitea"
 ---
 
 # Hacking on Gitea

docs/development/integrations.md

@@ -3,16 +3,8 @@ date: "2019-04-15T17:29:00+08:00"
 title: "Integrations"
 slug: "integrations"
 sidebar_position: 65
-toc: false
-draft: false
 aliases:
   - /en-us/integrations
-menu:
-  sidebar:
-    parent: "development"
-    name: "Integrations"
-    sidebar_position: 65
-    identifier: "integrations"
 ---
 
 # Integrations

docs/development/migrations.md

@@ -3,16 +3,8 @@ date: "2019-04-15T17:29:00+08:00"
 title: "Migrations Interfaces"
 slug: "migrations-interfaces"
 sidebar_position: 55
-toc: false
-draft: false
 aliases:
   - /en-us/migrations-interfaces
-menu:
-  sidebar:
-    parent: "development"
-    name: "Migrations Interfaces"
-    sidebar_position: 55
-    identifier: "migrations-interfaces"
 ---
 
 # Migration Features

docs/development/oauth2-provider.md

@@ -3,16 +3,8 @@ date: "2023-06-01T08:40:00+08:00"
 title: "OAuth2 provider"
 slug: "oauth2-provider"
 sidebar_position: 41
-toc: false
-draft: false
 aliases:
   - /en-us/oauth2-provider
-menu:
-  sidebar:
-    parent: "development"
-    name: "OAuth2 Provider"
-    sidebar_position: 41
-    identifier: "oauth2-provider"
 ---
 
 # OAuth2 provider