Solr precreate collection on start

[poikilotherm]

Hey folks,

while using testcontainers-solr to play with the Schema API, I noticed that my prepared images from ghcr.io/gdcc/solr-k8s did not create my prepared collection as intended.

This is usually done by setting CMD ["sh", "-c", "solr-precreate ${COLLECTION} ${CONFIGSETS_DIR}/${CONFIGSET}"], allowing me to ship and use prepared schema.

Within the SolrContainer class, the command is hardcoded to solr -f. May I suggest changing that to be configurable? I'd be happy to create a PR for that.

(I know about .withCollection(), but that will create a new, empty core. That might also be extended with a parameter to solr create_core to reuse the configset like with the precreation. Whatever seems a better fit to you folks)

Thx,
Oliver

P.S.: my Dockerfile is at https://github.com/gdcc/dataverse/blob/develop%2Bct/conf/solr/Dockerfile if you want to see more context.