feat: Introduce Location enum for improved location handling

- Added a new `Location` enum in `constants.py` to standardize
    location inputs across the application.
- Updated `text_search` function in `cli.py` to use `Location` type
    for `peo_in` and `inc_in` parameters.
- Modified `url_generator.py` to accept `Location` type for `peo_in`
    and `inc_in` in the `SearchQueryKwargs` class.
- Refactored tests in `test_url_generator.py` to validate the new
    `Location` enum usage.
- Enhanced test cases to ensure correct mapping of locations in\
    various contexts.

edgar_tool/cli.py

@@ -4,10 +4,9 @@
 
 import click
 import typer
-from dateutil.relativedelta import relativedelta
 from typing_extensions import Annotated
 
-from .constants import DateRange, FilingCategory
+from .constants import DateRange, FilingCategory, Location
 from .text_search import EdgarTextSearcher
 
 app = typer.Typer(name="edgar-tool", no_args_is_help=True)
@@ -92,7 +91,7 @@ def text_search(
         ),
     ] = None,
     peo_in: Annotated[
-        Optional[str],
+        Location,
         typer.Option(
             "--principal-executive-offices-in",
             "-peoi",
@@ -106,7 +105,7 @@ def text_search(
         ),
     ] = None,
     inc_in: Annotated[
-        Optional[str],
+        Location,
         typer.Option(
             "--incorporated-in",
             "-ii",