Add support for using the OpenTelemetry chloggen tool

[jvoravong]

Description

This PR brings several enhancements to the Makefile, introducing new utility functions, support for chloggen, and pre-commit checks.

Updated Makefile with New Actions

• install-tools: Installs required tools for CI/CD workflows using Homebrew and Go. Currently supports only MacOS and Linux.
• Changelog Management with chloggen: Added utility functions to create and manage changelog entries in .chloggen/. These entries will be used to automatically populate CHANGELOG.md during each release.
  • Pre-commit Check: Added a pre-commit hook that fails if a changelog entry is required. This is triggered when the Helm chart templates or rendered examples are updated.
• Other Utility Functions: Added another utility make help.

Testing

The changes were manually tested.

Documentation

• Updated CONTRIBUTING.md to reflect the new Makefile actions and the introduction of chloggen.

make help sample:

jvoravong@X splunk-otel-collector-chart % make help

Usage:
  make <target>

General
  help             Display Makefile help information for all actions

Initialization
  install-tools    Install tools (macOS/Linux)

Build
  repo-update      Update Helm repositories to latest
  dep-build        Build the Helm chart with latest dependencies from the current Helm repositories
  render           Render the Helm chart with the examples as input

Changelog
  chlog-available  Validate the chloggen tool is available
  chlog-new        Creates or updates a YAML file under .chloggen
  chlog-validate   Validates changelog requirements for pull requests
  chlog-preview    Provide a preview of the generated CHANGELOG.md file for a release
  chlog-update     Creates an update to CHANGELOG.md for a release entry from content in .chloggen

make chlog-release VERSION=0.85.0 sample:

# Changelog

## [0.85.0] - 2023-09-18

### 💡 Enhancements 💡

This Splunk OpenTelemetry Collector for Kubernetes release adopts the [Splunk OpenTelemetry Collector v0.84.0](https://github.com/signalfx/splunk-otel-collector/releases/tag/v0.84.0).

- `chart`: Add support for OpenTelemetry CHANGELOG.md generator tool, see [chloggen](https://github.com/open-telemetry/opentelemetry-operator/tree/main/.chloggen) ([#923](https://github.com/signalfx/splunk-otel-collector-chart/pull/923))
- `agent`: Update Splunk Fluentd HEC docker image to v1.3.3 ([#924](https://github.com/signalfx/splunk-otel-collector-chart/pull/924))

## [0.84.0] - 2023-09-11

[hughesjj]

looks good but want to know about that odd step name

[jvoravong]

Going to adopt changes from #917 before the next commit for this PR.

[jvoravong]

Addressed PR comments and separated code out where possible. Executing final testing in GitHub workflows and then this should be ready to review.

[atoulme]

Did you have a separate PR for the code you separated?

[atoulme]

LGTM, one nit

[jvoravong]

Did you have a separate PR for the code you separated?

Haven't created it yet. Will do shortly.