libarchive provides a "raw format" that returns a single fake entry
called 'data' and the data for that entry is the whole input archive.

We can use this raw format to handle the "single-file" archives for
which we had the special KArchive-based singlefile plugins.
The advantage is that libarchive supports more formats than KArchive. In
particular with this commit we add support for the following new
formats that KArchive cannot handle:

- application/zlib
- application/x-lz4
- application/x-lzip
- application/x-lrzip
- application/x-lzop

Note 1: This fake 'data' entry requires a bunch of small changes in different
places, for which we use the recently 'displayName' property of
Archive::Entry.

Note 2: the documentation of archive_read_support_format_raw says that
it should not be always enabled, so we only enable it if we have a
"single-file" mimetype. For this purpose we generate in cmake a
LIBARCHIVE_RAW_MIMETYPES define that will be automatically updated when
adding new future mimetypes.

BUG: 458908
FIXED-IN: 22.12.0