Add aws-smithy-observability and aws-smithy-observability-otel crates (#4003)

## Motivation and Context
<!--- Why is this change required? What problem does it solve? -->
<!--- If it fixes an open issue, please link to the issue here -->
This PR is an updated version of
#3912 and
#3986 moving back to the
`dyn Trait` based implementation since some issues came up in the review
of the Associated Types based implementation

## Description
<!--- Describe your changes in detail -->
Add two new crates
* `aws-smithy-observability` - contains traits for our observability
solution and a `global` module for managing the global telemetry
provider
* `aws-smithy-observability-otel` - contains an OpenTelemetry based
implementation of the traits

## Testing
<!--- Please describe in detail how you tested your changes -->
<!--- Include details of your testing environment, and the tests you ran
to -->
<!--- see how your change affects other areas of the code, etc. -->
Various unit tests in both new crates.

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
Note: leaving out a changelog entry for now since these crates won't
offer much value until we instrument our runtime crates in some
subsequent PRs

----

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choice._

---------

Co-authored-by: Zelda Hessler <zhessler@amazon.com>

Author: landonxjames

buildSrc/src/main/kotlin/CrateSet.kt

@@ -63,12 +63,14 @@ object CrateSet {
             "aws-smithy-compression",
             "aws-smithy-client",
             "aws-smithy-eventstream",
+            "aws-smithy-experimental",
             "aws-smithy-http",
             "aws-smithy-http-auth",
             "aws-smithy-http-tower",
             "aws-smithy-json",
             "aws-smithy-mocks-experimental",
-            "aws-smithy-experimental",
+            "aws-smithy-observability",
+            "aws-smithy-observability-otel",
             "aws-smithy-protocol-test",
             "aws-smithy-query",
             "aws-smithy-runtime",