integrations: Move configs in config_options to url_options.

Currently we have 2 implementations of `config_options`:

- It's used for generating optional webhook URL parameters. These
settings also come with custom UI in the "Generate integration URL"
modal.

- In `/bots` API, it's used as schema for the bots `BotConfigData`. Each
type of bots have different ways of defining their `BotConfigData`
fields. Currently, only embedded bots use `BotConfigData`, and only the
incoming webhooks use `config_options` to configure a bot's
`BotConfigData`; thus, the `config_options` remain unused.

To avoid confusion as to which implementation of `config_options` is
used by an integration, this separates the first use case -- to generate
optional webhook URL -- to a new field called `url_options`. Thus, the
`config_options` field is reserved only for the second use case.

zerver/lib/webhooks/common.py

@@ -61,6 +61,13 @@ class WebhookConfigOption:
     validator: Callable[[str, str], str | bool | None]
 
 
+@dataclass
+class WebhookUrlOption:
+    name: str
+    label: str
+    validator: Callable[[str, str], str | bool | None]
+
+
 def get_setup_webhook_message(integration: str, user_name: str | None = None) -> str:
     content = SETUP_MESSAGE_TEMPLATE.format(integration=integration)
     if user_name: