[UBP for individuals] Configure usage-based billing in personal settings

[jldec]

This lives in the Billing page at https://gitpod.io/billing in your personal settings, where we already show your team billing account if active.

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A new section on the same page should show personal UBP billing as inactive when no payment method has been configured.

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After configuring a payment mething the section shows the following, similar to team billing.

Tasks

Server

• Add new methods to server to support individual user signup:
  • Add createOrUpdateStripeCustomerForUser method ([UBP] Add server method to create a stripe customers for an individual user #12753)
  • Add findStripeSubscriptionId ([UBP] Add findStripeSubscriptionId method to server #12876)
  • Add getStripePortalUrl ([UBP] Add getStripePortalUrl method to server #12864)
  • Add (get|set)UsageLimit(attributionId) ([UBP] Add getUsageLimit and setUsageLimit methods to server #12767)
  • Add subscribeUserToStripe ([UBP] Add subscribeToStripe server method #12887)

UI

• Extract components common to both team and individual user UBP configuration ([UBP] Extract common UBP configuration components #12732)
• Add placeholder billing configuration UI to individual billing page ([UBP] Add placeholder billing configuration UI to the user settings page #12733)
• Hook up placeholder billing UI on the user settings page with the new server methods. ([UBP] Allow individual users to sign up for usage based pricing #12942)
• Remove team-specific Stripe APIs from server:
  • findStripeSubscriptionIdForTeam ([UBP] Remove team specific Stripe APIs from server JSON-RPC API #12957)
    • Need to remove one usage from BillingAccountSelector first ([UBP] Use findStripeSubscriptionId in BillingAccountSelector component #12954)
  • subscribeTeamToStripe ([UBP] Remove team specific Stripe APIs from server JSON-RPC API #12957)
  • getStripePortalUrlForTeam ([UBP] Remove team specific Stripe APIs from server JSON-RPC API #12957)
  • getUsageLimitForTeam ([UBP] Remove team specific Stripe APIs from server JSON-RPC API #12957)
  • setUsageLimitForTeam ([UBP] Remove team specific Stripe APIs from server JSON-RPC API #12957)

Other

• Make getCostCenter throw an error if no cost center exists. See this comment.