Add holmes generate alertmanager-tests command

[aantn]

and add flags to holmes investigate alertmanager to use that data instead of connecting to a live alertmanager

[Avi-Robusta]

for tests
poetry run python3 ./holmes.py investigate alertmanager --alertmanager-file ... when no url is specified you will get a pydantic exception

pydantic_core._pydantic_core.ValidationError: 1 validation error for Issue                                                                                                                                                                                                     
source_instance_id                                 

since it uses the url and its none in the alertmanager source
I would change the line in AlertManagerSource for source_instance_id to

        return [
            Issue(
                id=alert.unique_id,
                name=alert.name,
                source_type="prometheus",
                source_instance_id= self.filepath if self.filepath else self.url,

[Avi-Robusta]

LGTM,
2 changes requested

[aantn]

for tests poetry run python3 ./holmes.py investigate alertmanager --alertmanager-file ... when no url is specified you will get a pydantic exception

pydantic_core._pydantic_core.ValidationError: 1 validation error for Issue                                                                                                                                                                                                     
source_instance_id                                 

since it uses the url and its none in the alertmanager source I would change the line in AlertManagerSource for source_instance_id to

        return [
            Issue(
                id=alert.unique_id,
                name=alert.name,
                source_type="prometheus",
                source_instance_id= self.filepath if self.filepath else self.url,

Good catch, will fix.