Move data-access-objects to package debiki.dao.
Remove pointless HtmlConfig related code

- Remove DebikiHttp.newUrlConfig, move constants to HtmlConfig
- Only use HtmlConfig from within class HtmlForms (and let HtmlPageSerializer
  use a `hostAndPort: String` instead of a HtmlConfig).
- Remove linkTo(user, config)
Inline HtmlConfig in HtmlForms.
Patch page when comment deleted; show all unapproved stuff to admins

Also:
- Add class ShowUnapproved
- Have HtmlPageSerializer filter on ShowUnapproved in thread reply loop
- Let BrowserPagePatcher include unapproved stuff by the current user, by
  default.
- Add a simpler version of jsonForThreadsAndPosts().
Admin SPA: Show num flags in Activity tab.
Admin SPA: Don't open links in target="_blank", change <a> to <span>.
Include comment text and date in email notifications

And make some functions private.
Rename AutoApprover.scala.scala: remove ".scala".
Start WellBehaved-approve users after first manual approval.
Remove rate-own-comment tips

And remove a beige left-arrow-triangle from a .png file, which was used
only by the sort order tips.
Move trait PageTestValues to separate file.
Add PageParts utility functions.
Downweight ratings of own comment, add test suite.
Fix bug: Don't notify users of replies to own comment

The bug is a wrapping `Some(...)`. — Also make some functions private
and remove "_" prefix. And fix test suite bugs.
Fix bug by letting PostState.whenCreated set everything to None

Otherwise this:
  lastApprovalDati = ... Some(creationPostActionDto.creationDati)
becomes incorrect, if the post was initially preliminarily approved,
but that preliminary approval was later rejected.
Comment out tests that are broken since Patch.isDeleted = false.
Fix broken unit tests: use `postId` not `id`

Also edit comment.
Bump assets version link to /29/.
Add test implementation of full text searching

But I have not yet implemented the actual full text searching in the TenatDbDao.
Add Post.toJsonString() and Post.fromJsonString()

And require(postId == id).