Exclude unused libs under torch/lib. Reduce Debian package size by 700Mb

- libtorch_cuda.so (1Gb) and libtorch_cpu.so (700Mb) are large shared
  libs that are available at package root and under torch/lib.
- The top level imports are used, so they unused libs are removed from
  package
- This reduces the single file package size from 1.6Gb to 920Mb

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 +31,13 @@ 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_cpu.so')])
+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 +62,11 @@ 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,
+    )