[ENH] Schema updates

Alterations to db schema:

borehole:

• depth -> deleted
• bedrockdepth -> bedrockaltitude (in line with other depth-> altitude
• changes)
• name -> added (based on earlier request from Philipp)
• description -> added (based on earlier request from Philipp)

borehole section:

• topdepth -> topaltitude
• bottomdepth -> topaltitude
• measureddepth (added) description already exists for borehole section.

tests and serialization have been updated based on this.