<container> is not indexed at collection level

[alexduryee]

Many archival collections are only described at the collection level, as they are either very small (1 box or less) or unprocessed. These collections use <container> at the collection level (ead/archdesc/did) to associate containers with description.

ead2_component_config indexes containers, but ead2_config does not. The latter needs to, in order to associate/display container information with collection records.