feat: framework for sys events

[praveen-influx]

(not to merge)

Mainly PoC code,

• uses runtime reflection to dynamically create StructArray from an arbitrary event data
• it deviates from the original idea to allow querying select * from system.foo (where foo is the event type) and requires select * from system.events where event_type='foo' (there are ways to allow system.events.foo, but given both achieve similar result and this approach does not require changing SystemSchemaProvider, I parked it there)
• one big disadvantage is, it uses runtime reflection using bevy_reflect, which means events cannot have certain types as they're not supported by bevy_reflect crate. This includes Arc<str> and this may (or may not) be a show stopper. Also, there's no nesting support in this PR but I think it is doable though.
• because of runtime reflection, need to be extra careful in testing to make sure all the types are mapped correctly in arrow otherwise it results in runtime error.

closes: #25581