Update cloudfoundry-resources module to follow style guide

[Copilot]

This PR updates the cloudfoundry-resources module to comply with the OpenTelemetry Java Contrib style guide by making minimal changes focused on style improvements without altering functionality.

Changes Made

1. @autoservice Usage

• Added @AutoService annotations to CloudFoundryResourceProvider and CloudFoundryResourceDetector to automatically generate META-INF/services files
• Removed manual META-INF/services files that were previously maintained by hand
• Added necessary dependencies for @AutoService annotation processing

2. Final Class Declaration

• Made public non-internal classes final as recommended by the style guide:
  • CloudFoundryResourceProvider
  • CloudFoundryResourceDetector

3. Static Imports

• Added static imports for commonly used methods per style guide recommendations:
  • AttributeKey.stringKey in CloudFoundryResource
  • StandardCharsets.UTF_8, Collections.emptyMap, Collectors.joining, Assertions.fail in CloudFoundryResourceTest

Verification

• All existing tests continue to pass
• Build succeeds with proper formatting
• @autoservice correctly generates the same service provider files that were manually maintained
• No functional changes to the module behavior

The changes bring the module into full compliance with the documented style guide while maintaining backward compatibility and existing functionality.

Fixes #244.

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