inject the backend query type map for pluggable backend selection

[kroepke]

Description

always also bind backends in the generic map binder, even for versioned backends in non-versioned backends, use the map binder directly so the engine can pick the correct backend based on the BackendQuery instance used

for query normalization, ignore non-elasticsearch based queries for now, we will need to address normalizers later to make them type safe (or just live with the instanceof check)

/nocl

Simplified version of #21073

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would cause existing functionality to change)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Kay Roepke seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[kroepke]

screwed up the local user config on a new machine, I'll re-push this