Configure orchestrator's key components in builder's build method (#2802)

## Motivation and Context
Moves setting orchestrator components out of `ServiceRuntimePlugin` and
puts it in service config builders' build method.

## Description
This PR is the forth in a series of config refactoring. Here, we move
pieces of code out of `ServiceRuntimePlugin::config` method so that key
orchestrator components meant for the service-level config should only
be constructed once when a service config is created, e.g. during
builder's `build` method. Previously, those components were newly
created every time an operation is invoked.

Wherever `self.handle.conf...` is used, the PR has moved it from
`ServiceRuntimePlugin::config` to the builders' `build` method.

Note that there will be a separate PR to better handle auth resolver &
identity resolver in the context of the ongoing config refactoring.

## Testing
- [x] Passed tests in CI

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Co-authored-by: Yuki Saito <awsaito@amazon.com>