Use the src/ layout to fix packaging Khoj for PyPi

- Why
  The khoj pypi packages should be installed in `khoj' directory.
  Previously it was being installed into `src' directory, which is a
  generic top level directory name that is discouraged from being used

- Changes
 - move src/* to src/khoj/*
 - update `setup.py' to `find_packages' in `src' instead of project root
 - rename imports to form `from khoj.*' in complete project
 - update `constants.web_directory' path to use `khoj' directory
 - rename root logger to `khoj' in `main.py'
 - fix image_search tests to use the newly rename `khoj' logger
 - update config, docs, workflows to reference new path `src/khoj'

src/khoj/utils/yaml.py

@@ -0,0 +1,39 @@
+# Standard Packages
+from pathlib import Path
+
+# External Packages
+import yaml
+
+# Internal Packages
+from khoj.utils.rawconfig import FullConfig
+
+
+# Do not emit tags when dumping to YAML
+yaml.emitter.Emitter.process_tag = lambda self, *args, **kwargs: None  # type: ignore[assignment]
+
+
+def save_config_to_file(yaml_config: dict, yaml_config_file: Path):
+    "Write config to YML file"
+    # Create output directory, if it doesn't exist
+    yaml_config_file.parent.mkdir(parents=True, exist_ok=True)
+
+    with open(yaml_config_file, 'w', encoding='utf-8') as config_file:
+        yaml.safe_dump(yaml_config, config_file, allow_unicode=True)
+
+
+def load_config_from_file(yaml_config_file: Path) -> dict:
+    "Read config from YML file"
+    config_from_file = None
+    with open(yaml_config_file, 'r', encoding='utf-8') as config_file:
+        config_from_file = yaml.safe_load(config_file)
+    return config_from_file
+
+
+def parse_config_from_string(yaml_config: dict) -> FullConfig:
+    "Parse and validate config in YML string"
+    return FullConfig.parse_obj(yaml_config)
+
+
+def parse_config_from_file(yaml_config_file):
+    "Parse and validate config in YML file"
+    return parse_config_from_string(load_config_from_file(yaml_config_file))