[FEATURE] Ease previewing custom record data in workspace module

Currently only pages, pages_language_overlay and tt_content have
the possibility to open a preview in the website frontend.
A hook needs to be used to open the preview for custom records
(since possibly the location of the rendering plugin and its
page needs to be resolved).

To ease that behaviour a new Page TSconfig setting is added:
options.workspaces.previewPageId

Possibilities:
* options.workspaces.previewPageId = 123
* options.workspaces.previewPageId = field:pid
* options.workspaces.previewPageId.tx_myext_table = 123
* options.workspaces.previewPageId.tx_myext_table = field:pid

Resolves: #59144
Releases: 6.3
Change-Id: I44fffa6fffb1ccc8af79e6dea48415cdf281cb01