chore: migrate to v2 golangci-lint

[csatib02]

• Migrates golangci-lint to v2.
• Adds sensible default linters.
• Fixes linter errors.

[Copilot]

Pull Request Overview

This PR migrates golangci-lint to version 2 by updating the configuration file and making corresponding code changes to address linter complaints.

• Migrates the linter configuration from the old format to the new v2 format in .golangci.yml.
• Updates variable names and receiver references for consistency with linter recommendations.
• Adds nolint comments to test imports to satisfy new linting rules.

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/resources/otel_conf_gen/pipeline/components/exporter/otlphttp_exporter.go	Renamed variables for consistent HTTP casing.
pkg/resources/manager/tenant_resource_manager.go	Updated receiver variable from r to t for consistency.
controllers/telemetry/suite_test.go	Added nolint annotations to imported packages.
controllers/telemetry/route_controller.go	Updated lambda callbacks to ignore unused parameters with _.
controllers/telemetry/controller_integration_test.go	Similar nolint adjustments for test imports.
.golangci.yml	Reconfigured linters and formatters to support golangci-lint v2 structure.

Files not reviewed (1)

• Makefile: Language not supported