feat(billing): add account billing client

apps/web/src/app/billing/clients/account-billing.client.ts

@@ -0,0 +1,24 @@
+import { Injectable } from "@angular/core";
+
+import { ApiService } from "@bitwarden/common/abstractions/api.service";
+
+import { BillingAddress, TokenizedPaymentMethod } from "../payment/types";
+
+@Injectable()
+export class AccountBillingClient {
+  private endpoint = "/account/billing/vnext";
+  private apiService: ApiService;
+
+  constructor(apiService: ApiService) {
+    this.apiService = apiService;
+  }
+
+  purchasePremiumSubscription = async (
+    paymentMethod: TokenizedPaymentMethod,
+    billingAddress: Pick<BillingAddress, "country" | "postalCode">,
+  ): Promise<void> => {
+    const path = `${this.endpoint}/subscription`;
+    const request = { tokenizedPaymentMethod: paymentMethod, billingAddress: billingAddress };
+    await this.apiService.send("POST", path, request, true, true);
+  };
+}

apps/web/src/app/billing/clients/index.ts

@@ -1,2 +1,3 @@
 export * from "./organization-billing.client";
 export * from "./subscriber-billing.client";
+export * from "./account-billing.client";