[FR]: webpack-merge loader required

### What is the current behavior?

There is no loader present or available for webpack-merge feature

### Describe the feature

we are extensively relying on webpack-merge for different environments. Hence when trying to integrate to pipelines, getting error as webpack-merge module not present. Requesting someone to please help in this at the earliest or just a workaround to handle this scenario.

As i can see there was no webpack-merge loader present here: https://github.com/aspect-build/rules_webpack/tree/main/webpack/private

**Error:**
```
[webpack-cli] Error: Cannot find module 'webpack-merge'
Require stack:
- /home/mshreevatsa/.cache/bazel/_bazel_mshreevatsa/3f4e838ef516b7be58a7450ce5de6643/sandbox/linux-sandbox/315/execroot/cn2/bazel-out/k8-fastbuild/bin/ui/web/webpack.config.js
- /home/mshreevatsa/.cache/bazel/_bazel_mshreevatsa/3f4e838ef516b7be58a7450ce5de6643/sandbox/linux-sandbox/315/execroot/cn2/bazel-out/k8-opt-exec-2B5CBBC6/bin/ui/web/_bundle_webpack_binary.sh.runfiles/cn2/ui/web/node_modules/.aspect_rules_js/webpack-cli@5.1.4_33992988/node_modules/webpack-cli/lib/webpack-cli.js
```

Start by inspecting the webpack/private directory and the referenced webpack.config.js usage, then reproduce the Bazel pipeline failure showing that webpack-cli cannot find webpack-merge. Determine how dependencies are made available to the webpack bundle. Done means a pipeline using webpack-merge no longer reports the missing-module error.

Written by the indexing model from the issue text.