Add new ESQL CCS challenge in Logs

[gbanasiak]

The PR adds new esql-ccs-snapshot challenge in elastic/logs which reuses existing ESQL queries but executes them in CCS context.

The challenge has 2 modes of operation:

• skip_esql_ccs_remote_clusters: true - queries are sent only to the local cluster
• skip_esql_ccs_remote_clusters: false - queries are sent only to remote clusters

[favilo]

Left some style comments, but it looks good overall

[gbanasiak]

@elasticmachine update branch

[luigidellaquila]

LGTM, thanks @gbanasiak!

I like the idea of making the tasks conditional and using them for both single cluster and CCS (rather than creating a separate set of tasks). This will ensure that we keep them aligned, so that we can compare them and evolve them together.