Update all Solr references from 8.11.1 to 9.3.0 and
make sure you can spin up containers.

schema.xml was copied from
solr-9.3.0/server/solr/configsets/_default/conf/managed-schema.xml

(Note managed-schema.xml as there is no schema.xml upstream.)

solrconfig.xml was copied from
solr-9.3.0/server/solr/configsets/_default/conf/solrconfig.xml

API tests will fail, of course, because we have not yet added
our Dataverse-specific config. We'll be moving it from these
files and then deleting them:

conf/solr/8.11.1/schema.xml
conf/solr/8.11.1/solrconfig.xml

"To improve security, XSLTResponseWriter has been moved
to the scripting Module instead of shipping as part of
Solr core. This module needs to be enabled explicitly."

-- https://github.com/apache/solr/blob/main/solr/solr-ref-guide/modules/upgrade-notes/pages/major-changes-in-solr-9.adoc

See also https://stackoverflow.com/questions/74118537/solr-9-org-apache-solr-common-solrexceptionorg-apache-solr-common-solrexcepti

Conflicts:
downloads/download.sh
scripts/vagrant/setup.sh

Instead of keeping the XML file originating from Solr 7 around,
let's put our customisations in the vanilla config.

The indentation changed, so this looks like an "everything changed"
thing.

Aside from that, we are doing three changes:
1. Enable ClassicIndexSchemaFactory
2. Disable schemaless via "update.autoCreateFields:false"
3. Tweak our searches in /select request handler

- No longer use Trie*Fields, switch all to point fields (Trie has been
  deprecated since 9)
- Add some new field types added since Solr 9 came out

…template

Rebase on vanilla Solr 9.3

This reverts commit 8d37b0f.

We don't need the scripting module anymore.

…rching with token will always find things

…th Solr searches