refactor(core): split web entry from core (#6082)

This pr is trying to split `web` and `electron` entries from `core`. It allows more platform-related optimization to be addressed in each entry.
We should remove all browser/electron only codes from `core` eventually, this is the very first step for that.

scripts/setup/global.ts

@@ -1,7 +1,6 @@
+import { getRuntimeConfig } from '@affine/cli/src/webpack/runtime-config';
 import { setupGlobal } from '@affine/env/global';
 
-import { getRuntimeConfig } from '../../packages/frontend/core/.webpack/runtime-config';
-
 globalThis.runtimeConfig = getRuntimeConfig({
   distribution: 'browser',
   mode: 'development',