[Bug] Robustly detect sections and subsections for nested fields

[hlmore]

Description:

Currently Beaverdam splits paths to fields using periods (.) as the delimiter. If a section or field name contains a period, it also gets split, making the path to he field incorrect.

Suggested steps to solve:

Use a less-normal character than . to split paths. Perhaps use / or \ like in filesystem paths, or set a sequence of characters as the delimiter instead.

Currently the code controlling splitting behaviour is line 181 in metadatasource.py.