Data migration script from kvalobs and KDVH

[intarga]

No description provided.

[lcoram]

https://gitlab.met.no/oda/oda/-/blob/main/tools/kdvh-importer/dataandflags.go?ref_type=heads#L105
If we look inside each of the CustomDataFunction: sections for this list of tables, you could hopefully take the information that is currently being wrapped in a oda.timeseriesdata at the end of the function and insert it appropriately into the data and flags tables.
Two alternatives:

1. stick with the golang code, and rewrite the part that puts it into ODA to write to appropriately formated file. Then stream that in a similar way to mentioned below?
2. understand where the dump files are, and read them in as more appropriately formated data for potentially reusing the way of using stdin.

NOTE: all data from kdvh could just be written to correct (no original value). Maybe makes more sense, since KDVH ostensibly only stores one value (and it is the corrected one)?

Validation - at least need very good error reporting / handling to ensure that we know all data we tried to write was written. Otherwise need to run through the dumps a second time, to confirm all rows now exist in the database.