Pass request to filter factories

[alukach]

Currently, we pass a simple dictionary to the filter_builder:

stac-auth-proxy/src/stac_auth_proxy/middleware/Cql2BuildFilterMiddleware.py

Lines 79 to 90 in 0ba2237

	filter_expr = await filter_builder(
	{
	"req": {
	"path": request.url.path,
	"method": request.method,
	"query_params": dict(request.query_params),
	"path_params": requests.extract_variables(request.url.path),
	"headers": dict(request.headers),
	},
	**scope["state"],
	}
	)

We should ensure that the request itself is exposed to the filter factory, enabling access to any available property within that request (such as DB connections that are available on the request.app).