Make keyboard shortcuts optional

In addition to the `{{docs-keyboard-shortcuts}}` component, there are some keyboard shortcuts baked into `controllers/application.js` and `docs-viewer/component.js` that are enabled on initialization. These can interfere with components that have custom keyboard interactions.

A configuration option that disables shortcut initialization could solve this issue for some users.

从 controllers/application.js 和 docs-viewer/component.js 开始，跟踪初始化期间启用的键盘快捷键以及当前处理配置的方式。定义配置入口点，并验证禁用该入口点会阻止这些快捷键，同时保留 {{docs-keyboard-shortcuts}} 组件的行为。

由索引模型根据 Issue 内容生成。