Change base_url handling in API

[lukas-phaf]

Remove code with misleading comments which does not achieve anything.

This should be double-checked on the test system to make sure it works with the proxy configuration.

[github-actions]

Unit Test Coverage Report

File	Stmts	Miss	Cover	Missing
__init__.py	0	0	100%
datastore_pb2.py	61	48	21%	34–81
datastore_pb2_grpc.py	54	27	50%	15–16, 19, 65–80, 121–123, 128–130, 135–137, 142–144, 148–173, 219, 246, 273, 300
export_metrics.py	10	0	100%
grpc_getter.py	20	11	45%	15–24, 28–31, 35–37, 41–43
main.py	45	7	84%	51, 56, 66, 76–77, 87–88
metadata_endpoints.py	69	32	54%	50–59, 63, 115, 130–257, 261
response_classes.py	5	0	100%
utilities.py	177	36	80%	21, 39, 46, 68–71, 79–90, 95, 115, 119, 121, 149, 155, 173, 231–237, 241–243, 273, 277, 299, 304
custom_geo_json
edr_feature_collection.py	6	0	100%
formatters
__init__.py	11	0	100%
covjson.py	60	1	98%	91
geojson.py	21	2	90%	27, 52
openapi
custom_dimension_examples.py	4	0	100%
edr_query_parameter_descriptions.py	11	0	100%
openapi_examples.py	13	0	100%
openapi_metadata.py	1	0	100%
routers
__init__.py	0	0	100%
edr.py	101	4	96%	348–349, 438–439
feature.py	47	19	60%	99–132, 148–153, 159–181
TOTAL	716	187	74%

Title	Coverage	Tests	Skipped	Failures	Errors	Time
API Unit Tests		40	0 💤	0 ❌	0 🔥	1.957s ⏱️
Ingest Unit Tests		16	0 💤	0 ❌	0 🔥	11.805s ⏱️

[Teddy-1000]

Confirmed correct behind proxy.