Page - change notificationDrawer props to be more generic

re: https://github.com/patternfly/patternfly-react/issues/8541#issuecomment-1384624420

There are currently a props on the <Page> component (notificationDrawer and isNotificationDrawerExpanded) that attach a drawer to the page. AFAIK there is no requirement to use a notification drawer there - the props just update the page to support a drawer that appears over the main content area. Assuming we don't want to limit that use of a drawer in the page to notification drawer only, I wonder if it makes sense to rename those props to something more generic so it's clear it can be used for any sort of drawer content.

cc @mcarrano @mceledonia @tlabaj

Jira Issue: PF-141

Pageコンポーネントから始めて、notificationDrawer propとisNotificationDrawerExpanded prop、およびそれらの使用箇所を検索します。drawerのコンテンツに期待される汎用的な命名を確認し、影響を受ける参照を更新して、Pageのdrawerの動作が変わらないことを検証します。