MIDS levels included as part of the Information Elements

[matdillen]

At the bottom of the Information Elements page, the levels are listed as part of the Information Elements. There is also a broken table for Media, due to a mismatch between the terms and mappings source files (different case).

• We need to ensure the terms, levels and mappings source files match with each other .
• The mappings files on StaDocGen are not fully up to date compared to the MIDS repo (e.g. addition of object_label and subject_label; addition of mids namespace to subject_category; fixing the case of the media information element).

[emhaston]

See #127