Plug-and-play metainfo not working on v1.1.0

When trying to run the infrastructure for v1.1.0 (eb5f18f7), the dynamically imported ElasticSearch extensions from EELSDBParser (results.properties.spectroscopy.eels) are not working.

When launching the app with no ES indices, the mapping does not contain the EELS quantities, and also the API will fail upon trying to fetch this information. The parsing of EELS entries goes through fine.

This issue is also preventing the addition of the nexus ES annotations, as they would rely on the same plug-and-play metainfo extension mechanism that EELSDBParser is using.

Problem seems to be in nomad/parsing/parsers.py, where the EELSDBParser is no longer imported at the top, but only imported dynamically later through MatchingParserInterface.mainfile_parser.