feat(clients): Add v2 API clients and centralize client generation (#522)

This allows the new v2 APIs of ZITADEL to be used.

BREAKING CHANGE: The modules for client instantiation
have changed. There is no module "with access token"
or "with service account" anymore. Instead, there is a
centralized `ClientBuilder` in the clients module of the
api to create and configure the gRPC clients. The new
builder allows configuring auth methods beforehand
and then create the according client out of it.

Author: buehler

examples/fetch_profile_with_pat.rs

@@ -1,14 +1,15 @@
-use zitadel::api::{
-    clients::with_access_token::create_auth_client, zitadel::auth::v1::GetMyUserRequest,
-};
+use zitadel::api::{clients::ClientBuilder, zitadel::auth::v1::GetMyUserRequest};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     const PERSONAL_ACCESS_TOKEN: &str =
         "dEnGhIFs3VnqcQU5D2zRSeiarB1nwH6goIKY0J8MWZbsnWcTuu1C59lW9DgCq1y096GYdXA";
     const ZITADEL_URL: &str = "https://zitadel-libraries-l8boqa.zitadel.cloud";
 
-    let mut client = create_auth_client(ZITADEL_URL, PERSONAL_ACCESS_TOKEN).await?;
+    let mut client = ClientBuilder::new(ZITADEL_URL)
+        .with_access_token(PERSONAL_ACCESS_TOKEN)
+        .build_auth_client()
+        .await?;
     let user = client.get_my_user(GetMyUserRequest {}).await?.into_inner();
     println!("{:#?}", user);
 

examples/fetch_profile_with_service_account.rs

@@ -1,5 +1,5 @@
 use zitadel::{
-    api::{clients::with_service_account::create_auth_client, zitadel::auth::v1::GetMyUserRequest},
+    api::{clients::ClientBuilder, zitadel::auth::v1::GetMyUserRequest},
     credentials::{AuthenticationOptions, ServiceAccount},
 };
 
@@ -14,15 +14,16 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     }"#;
     const ZITADEL_URL: &str = "https://zitadel-libraries-l8boqa.zitadel.cloud";
     let service_account = ServiceAccount::load_from_json(SERVICE_ACCOUNT)?;
-    let mut client = create_auth_client(
-        ZITADEL_URL,
-        &service_account,
-        Some(AuthenticationOptions {
-            api_access: true,
-            ..Default::default()
-        }),
-    )
-    .await?;
+    let mut client = ClientBuilder::new(ZITADEL_URL)
+        .with_service_account(
+            &service_account,
+            Some(AuthenticationOptions {
+                api_access: true,
+                ..Default::default()
+            }),
+        )
+        .build_auth_client()
+        .await?;
     let user = client.get_my_user(GetMyUserRequest {}).await?.into_inner();
     println!("{:#?}", user);