library: seed label templates/layouts, default item type, fix Apache setup

- Seed Avery 5160/5167 and Demco spine templates plus Spine, Spine+barcode
  and Barcode-only layouts (Dewey call number split across lines)
- Default 942$c (item type) to BOOK so a Z39.50 import saves without edits
- Enable Plack includes in addition to the plain ones (static files/rewrites)
- Swap Apache from mpm_itk to prefork after koha-create (itk can't switch
  users in a container and returned HTTP 500 on every page)
- Drop unneeded SETUID/SETGID caps

Verified live: staff login, Z39.50 search/import against a local server,
save + auto barcode, label PDF with Dewey spine + barcode.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013wi3ZSot4XbUViwRFgLpRf

library/koha/bootstrap.pl

@@ -90,6 +90,12 @@ my $admin = Koha::Patron->new({
 })->store;
 $admin->set_password({ password => $env{admin_pass}, skip_validation => 1 });
 
+# ---- Make "add a book" need as few decisions as possible -------------------
+# The item type (942$c) is mandatory in Koha's frameworks; default it to Book so
+# a Z39.50 import can be saved without touching that field.
+$dbh->do(q{UPDATE marc_subfield_structure SET defaultvalue = 'BOOK'
+           WHERE tagfield = '942' AND tagsubfield = 'c'});
+
 # ---- Preferences ----------------------------------------------------------
 my %prefs = (
     autoBarcode              => 'incremental',  # new items get a barcode automatically