Reduce Debian, Mac App Size. Remove unused libraries under Torch/Lib

## Changes
- On **Debian**
  - `libtorch_cuda.so` (1Gb) and `libtorch_cpu.so` (700Mb) are large shared libs
  - They are available at package root and under `torch/lib` directory in the package
  - We remove the unused, duplicate libraries from under `torch/lib` as only the top level libraries are used
- On **Mac**
  - Remove `libtorch_{cpu,python}.dylib` under `torch/lib` directory from the Mac app.

## App Size Reduction
  - **Debian amd64** app size by **42%** from **1.6Gb to 920Mb**  
  - **Mac arm64** app by **15%** from **190Mb to 160Mb**
  - **Mac amd64** app by **33%** from **340Mb to 230Mb**

## Reference
- [Release Workflow Run](https://github.com/debanjum/khoj/actions/runs/2878104171) after changes
- [Release Workflow Run](https://github.com/debanjum/khoj/actions/runs/2869906116) before changes

.github/workflows/release.yml

@@ -49,9 +49,9 @@ jobs:
         run: |
           # Setup Environment for Reproducible Builds
           export PYTHONHASHSEED=42
-          export SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct
+          export SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)
 
-          pyinstaller Khoj.spec
+          pyinstaller --noconfirm Khoj.spec
           if [ "$RUNNER_OS" == "Windows" ]; then
             mv dist/Khoj.exe dist/khoj_"$GITHUB_REF_NAME"_amd64.exe
           fi

Khoj.spec

@@ -1,4 +1,6 @@
 # -*- mode: python ; coding: utf-8 -*-
+from os.path import join
+from platform import system
 from PyInstaller.utils.hooks import copy_metadata
 
 datas = [('src/interface/web', 'src/interface/web')]
@@ -29,6 +31,17 @@ a = Analysis(
     cipher=block_cipher,
     noarchive=False,
 )
+
+# Filter out unused, duplicate shared libs under torch/lib
+torch_lib_path = set([
+                join('torch', 'lib', 'libtorch_cuda.so'),
+                join('torch', 'lib', 'libtorch_cuda.dylib'),
+                join('torch', 'lib', 'libtorch_cpu.so'),
+                join('torch', 'lib', 'libtorch_cpu.dylib'),
+                join('torch', 'lib', 'libtorch_python.so'),
+                join('torch', 'lib', 'libtorch_python.dylib')])
+a.datas = [entry for entry in a.datas if not entry[0] in torch_lib_path]
+
 pyz = PYZ(a.pure, a.zipped_data, cipher=block_cipher)
 
 exe = EXE(
@@ -53,9 +66,11 @@ exe = EXE(
     entitlements_file=None,
     icon='src/interface/web/assets/icons/favicon.icns',
 )
-app = BUNDLE(
-    exe,
-    name='Khoj.app',
-    icon='src/interface/web/assets/icons/favicon.icns',
-    bundle_identifier=None,
-)
+
+if system() == 'Darwin':
+    app = BUNDLE(
+        exe,
+        name='Khoj.app',
+        icon='src/interface/web/assets/icons/favicon.icns',
+        bundle_identifier=None,
+    )