Improve telemetry; more modular Auth API

[joshcanhelp]

Changes

Add module Auth0::Mixins::Headers to handle telemetry headers more easily; add environmental telemetry (Ruby and Rails versions). This will make it easier to use Auth0::Api::AuthenticationEndpoints on its own like so:

class StaticPagesController < ApplicationController

  include Auth0::Api::AuthenticationEndpoints
  include Auth0::Mixins::HTTPProxy
  include Auth0::Mixins::Headers

  before_action :set_auth0_vars, only: %i[process_login_ro]

  def process_login_ro
    login_ro = params[:login_ro]
    response = login_with_resource_owner(login_ro[:email], login_ro[:password])
  end

  private

  def set_auth0_vars
    @domain = ENV['AUTH0_RUBY_DOMAIN']
    @client_id = ENV['AUTH0_RUBY_CLIENT_ID']
    @client_secret = ENV['AUTH0_RUBY_CLIENT_SECRET']
    @base_uri = "https://#{@domain}"
    @headers = client_headers
  end
end

References

This addresses an internal telemetry requirement while also making it easier to handle situations like this.

Testing

• This change adds unit test coverage
• This change has been tested on the latest version of Ruby

Checklist

• All existing and new tests complete without errors
• Rubocop passes on all added/modified files
• All active GitHub checks have passed

[machuga]

Looks good overall! Just nitpicking you :)

[machuga]

Can you update this to use {} syntax, as this repo seems to use more of a Weirich-style block syntax? (meaning it will also match the above)

[joshcanhelp]

@machuga - Fixed up!