feat(oidc): OIDC Prompt Support (#519)

* feat(oidc): OIDC Prompt Support

Boundary OIDC method does not currently support passing in prompts during authentication. This change adds the capability of passing OIDC prompts. Prompts are optional OIDC parameters that determine the behaviour of the authentication server: https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest

Add new optional `prompts` option to `boundary_auth_method_oidc` resource. `prompts` option are optional OIDC parameters that determine the behavior of the authentication server.

docs/resources/auth_method_oidc.md

@@ -31,6 +31,30 @@ resource "boundary_auth_method_oidc" "vault" {
   signing_algorithms = ["RS256"]
   type               = "oidc"
 }
+
+resource "boundary_auth_method_oidc" "oidc_with_one_prompt" {
+  api_url_prefix     = "https://XO-XO-XO-XO-XOXOXO.boundary.hashicorp.cloud:9200"
+  client_id          = "eieio"
+  client_secret      = "hvo_secret_XO"
+  description        = "My Boundary OIDC Auth Method With Prompt"
+  issuer             = "https://sts.windows.net/TENANT_ID/"
+  scope_id           = "global"
+  signing_algorithms = ["RS256"]
+  prompts            = ["select_account"]
+  type               = "oidc"
+}
+
+resource "boundary_auth_method_oidc" "oidc_with_multiple_prompts" {
+  api_url_prefix     = "https://XO-XO-XO-XO-XOXOXO.boundary.hashicorp.cloud:9200"
+  client_id          = "eieio"
+  client_secret      = "hvo_secret_XO"
+  description        = "My Boundary OIDC Auth Method With Multiple Prompts"
+  issuer             = "https://sts.windows.net/TENANT_ID/"
+  scope_id           = "global"
+  signing_algorithms = ["RS256"]
+  prompts            = ["consent", "select_account"]
+  type               = "oidc"
+}
 ```
 
 <!-- schema generated by tfplugindocs -->
@@ -57,6 +81,7 @@ resource "boundary_auth_method_oidc" "vault" {
 - `issuer` (String) The issuer corresponding to the provider, which must match the issuer field in generated tokens.
 - `max_age` (Number) The max age to provide to the provider, indicating how much time is allowed to have passed since the last authentication before the user is challenged again. A value of 0 sets an immediate requirement for all users to reauthenticate, and an unset maxAge results in a Terraform value of -1 and the default TTL of the chosen OIDC will be used.
 - `name` (String) The auth method name. Defaults to the resource name.
+- `prompts` (List of String) The prompts passed to the identity provider to determine whether to prompt the end-user for reauthentication, account selection or consent. Please note the values passed are case-sensitive. The valid values are: `none`, `login`, `consent` and `select_account`.
 - `signing_algorithms` (List of String) Allowed signing algorithms for the provider's issued tokens.
 - `state` (String) Can be one of 'inactive', 'active-private', or 'active-public'. Currently automatically set to active-public.
 - `type` (String) The type of auth method; hardcoded.