Set extract_tags call prior exclude_fields

[berghauz]

Hi!
Propose to set extract_tags call prior exclude_fields, coz in case of needs to pull tags from already existent filelds its deleted before plugin can store it in tags. If not to change it this tags will store in influxdb twice: as tags and as extra fields.
What to commit:

• set extract_tags call prior exclude_fields (also @measurement)
• add mutate clause to be able remove "host" from exclude_fields in test pipeline, coz it somewhat a workaround near host=testing-worker-linux-docker-85c5f992-3430-linux-14
• add mutate to development dependencies

Example below i have use in production:
influxdb{
send_as_tags => ["host","cc-group","acs-service"]
measurement => "%{schema}"
use_event_fields_for_data_points => true
exclude_fields => ["@Version","@timestamp","type","sequence","schema","host","cc-group","acs-service"]
}