proof of concept for npx convex self-host (#33831)

create a proof of concept for an `npx convex self-host` subcommand, with `npx convex self-host dev` beneath it. eventually we should put lots of other commands beneath it too.

To avoid code duplication, move the deployment-agnostic code to `devAgainstDeployment`, and deployment-agnostic CLI options to our `Command.prototype` override, and deployment-agnostic CLI option validation to `validateDevOptions`. Thus all of the shared functionality can use shared code.

GitOrigin-RevId: 0a0f330c35e306f631cd9fae4fcff77b1625963e

Author: ldanilek

npm-packages/convex/src/cli/configure.ts

@@ -159,7 +159,7 @@ export async function deploymentCredentialsOrConfigure(
   return { deploymentName, url, adminKey };
 }
 
-async function handleManuallySetUrlAndAdminKey(
+export async function handleManuallySetUrlAndAdminKey(
   ctx: Context,
   cmdOptions: { url: string; adminKey: string },
 ) {