RUM-3060 feat: Deprecate Alamofire extension pod

[ncreated]

What and why?

📦 Starting from 2.5.0, RUM can automatically track Alamofire requests, making the DatadogAlamofireExtension pod obsolete. Maintaining this pod is cumbersome as it adds an extra code path to the network instrumentation logic, which became problematic in issue #1638.

The new network instrumentation API introduced in 2.5.0 can handle Alamofire requests without requiring a separate pod. This solution also works for SPM, Carthage, and XCFramework integration. This PR deprecates DatadogAlamofireExtension in favor of the new instructions explained in the following documentation PR:

• RUM-3060 Add docs for RUM iOS SDK Integrated Libraries documentation#24253

How?

• Created RUM-3060 Add docs for RUM iOS SDK Integrated Libraries documentation#24253 to explain how to instrument Alamofire (and Apollo GraphQL) requests;
• DatadogAlamofireExtension.podspec is marked deprecated;

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

[maxep]

Nice!

[ganeshnj]

do we need to publish a version in order deprecate?

Can we simply delete this? So when customer tries to update (it is customer trigger action) they see an error and fix the issue instead keep using the deprecated version.

[ncreated]

We aim at deprecation not removal. The DatadogAlamofireExtension will continue to work for all customers in next releases until we finally delete it (in 3.0.0).

The deprecated = true will produce a warning during pod update indicating that this pod is being sunsetted. Customers are expected to follow the notice from pod description and land on https://docs.datadoghq.com/real_user_monitoring/mobile_and_tv_monitoring/integrated_libraries/ios (available once DataDog/documentation#24253 is merged) to instrument Alamofire using our URLSessionInstrumentation directly.