fix: open blog pages in the blog editor from every entry point

[erwinwalterddf]

Fixes #89

Two changes:

• sw-cms-detail override (new, extension/sw-cms/page/sw-cms-detail/index.js): before loading, look up the werkl_blog_entry that references the page and redirect to blog.module.detail. Orphaned blog_detail pages and regular layouts keep opening in the core editor; a failing lookup falls through to the core editor as well. sw-cms-create extends sw-cms-detail and has no route id, so it is not affected.
• init/cms-page-type.init.js: register the blog_detail page type with hideInList: true. In the 6.7 administration getVisibleTypes() is only used by the layout wizard, so the type disappears from "Create layout" while the "Blog page" filter in the layout list (getTypes()) stays as it is. This replaces the wizard override first proposed in Open blog pages in the blog editor from every entry point and hide the blog page type from the layout wizard #89 with the core mechanism meant for it.

Details and reasoning in #89.

Tested

Shopware 6.7.10.2, OpenBlogware 5.3.0, patch applied to the installed package and the administration rebuilt:

• #/sw/cms/detail/<pageId> of a blog entry → redirected to #/blog/module/detail/<entryId>.
• A blog_detail page without linked blog entry and a regular shop page → stay in the core editor.
• Layout wizard offers shop page, landing page, category page, product page and (third-party) bundle page; "Blog page" is gone. The "Blog page" filter in the layout list is unchanged.

[erwinwalterddf]

Update: the wizard override is not needed, the page type can be registered with hideInList: true instead (only the layout wizard uses getVisibleTypes() in 6.7). The PR reflects that.