chore: Refactored tooling for best practices

[stevehipwell]

This PR refactors the provider tooling to align it to GitHub Actions best practices and TF provider best practices. The following things have changed, but there shouldn't be a material change in how the project works.

• Fixed all GitHub Actions to a SHA with the version in a comment so Dependabot can keep them up to date but the runs are idempotent (to the checked in code)
• Added Dependabot group support to make GitHub Actions & Go module dependency changes easier to manage when they're not major versions
• Updated the setup Go GH action to use the Go version in go.mod instead of needing to copy the current version throughout the codebase.
• Added a terraform-registry-manifest.json file as per best practices
• Updated the golangci-lint config to the recommended pattern
• Commented out failing linting rules in .golangci.yml
• Updated the goreleaser config

[stevehipwell]

@kfcampbell I've replied to your questions.

[stevehipwell]

@kfcampbell I've rebased this ready to be merged.