Rethink extension build time instantiation of DefaultCamelContext

[jamesnetherton]

There's a few places outside of the CQ core where extensions explicitly instantiate their own DefaultCamelContext so that they can use it to pre-load stuff or get access to Camel resources in order to do build time enhancements.

This feels a bit heavyweight and has some limitations:

• It slows down the build time code. Especially if you have all extensions that create DefaultCamelContext on the classpath.

• It spams the build time logs with CamelContext messages which is potentially confusing for folks.

• Occasionally we need to do special patches to fix issues (see Camel OpenTelemetry not compatible with Quarkus OpenTelemetry #6642). The service discovery mechanism we have for FastCamelContext does not apply to DefaultCamelContext. So we loose the ability to easily exclude / include services etc.

Maybe there's a more lightweight way to do things or have 'just enough' CamelConext to fulfil whatever build time requirements these extensions have.