Provide parser for ingesting Avinor AWOS data

[jo-asplin-met-no]

For the Frost ingest activity, we currently ingest observations from two sources: Avinor and NMBU.
Frost has been extended with an ingest hook that could modify the data before passing it on to the lard ingestor.
The Avinor data need to be translated to MET-specific parameter IDs etc., while the NMBU data can be ingested directly as they are (even with the type ID set).

We need to decide which one of the following two options would be best:

1. Provide a parser in the lard ingestor for the Avinor data (and possibly also the NMBU data) so that Frost can merely pass it directly to the lard ingestor.
2. Do all parsing in Frost and pass the data along to the lard ingestor as if it would have come directly from Obsinn (where a parser already exists).