collect metrics and output a bill

[meherhendi]

• get metrics for each billing account.
• get namespace metrics from Kubecost.
• verify connection to Kubecost, Rancher, and Kubernetes APIs is working at all times (before every billing operation), and send an alert when the connection is lost.
• calculate bill using collected metrics for each project under the pay-per-use model: the balance is calculated and updated every 1 hour.
• generate a bill and save it in object storage using these conditions:
  • • under pay-per-use model: current date is 5 days away from the next billing cycle
  • • under pay-per-use model: the account reaches critical balance.
  • • under plan model: current date is 5 days away from the next billing cycle.
• send an email to each billing account's billingAdmins admins.