[awsappsignals] Add hostname as an emf attribute for generic (onprem)

[lisguo]

Description of the issue

For on prem customers of appsignals they are missing the hostname attribute to emf. This PR adds the hostname attribute by adding to the allowlist in the awsappsignals processor, and emitting it via emfexporter.

Description of changes

• Changes the awsappsignals processor to include hostname attribute from resourcedetection processor
• Changes emf config to include hostname

License

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Tests

unit test

Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint