🐛 OTLP forwarder should not nest the configuration

[linkdd]

Decision Record

The OpenTelemetry forwarder's datamodel had a nested Config field which was ignored by the editor in the Web UI.

It also embedded an *http.Client in the structure, in an attempt to cache it, but the forwarder structure is instantiated for every log (we should look into this later on by the way), so it is not a useful optimization at this point.

Changes

• 🐛 🗃️ Do not nest the OTLP configuration
• ♻️ Simplify OTLP forwarder code

License Agreement

• I guarantee that I have the rights on the code submitted in this PR
• I accept that this contribution will be released under the terms of the MIT License

[github-actions]

	Tests	Passed ✅	Skipped	Failed
API End-To-End Test Report	21 ran	21 passed	0 skipped	0 failed

• View API End-To-End Test Report

[github-actions]

	Tests	Passed ✅	Skipped	Failed
Consul End-To-End Test Report	1 ran	1 passed	0 skipped	0 failed

• View Consul End-To-End Test Report

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
22	0	0	22	100	2m22.515892s

Passed Tests

Name	⏱️ Duration	Suite
Create and Delete Personal Access Token	37.627 s	Account
Change Password	5.764 s	Account
Restore Password	4.892 s	Account
Create test role	5.073 s	Admin
Create test user	5.022 s	Admin
Log as test user	3.693 s	Admin
Login With Valid Credentials	3.702 s	Auth
Login With Invalid Credentials	3.393 s	Auth
Logout	4.303 s	Auth
Create new forwarder	4.738 s	Forwarders
Configure forwarder	4.983 s	Forwarders
Delete forwarder	4.614 s	Forwarders
Create new stream	4.995 s	Storage
Configure stream	4.937 s	Storage
Delete stream	4.561 s	Storage
View logs sent on default pipeline	6.327 s	Stream-Viewer
View logs sent via Syslog (RFC 5424)	5.768 s	Stream-Viewer
View logs sent via Syslog (RFC 3164)	5.799 s	Stream-Viewer
Watch logs	6.874 s	Stream-Viewer
Create new transformer	4.829 s	Transformers
Configure transformer	6.132 s	Transformers
Delete transformer	4.489 s	Transformers