Add integration tests for 5D and 6D segy_to_mdio

[markspec]

OBN will potentially be read as ingested as 6D:

• receiver line
• receiver point with line
• receiver component (e.g. hydrophone, vertical component etc)
• shot line
• shot point within line
• time

Streamer data could be ingested as:

• shot line
• shot point within line
• cable
• channel
• time