[DOC] Better articulation of the data format and file naming conventions

[eleanorfrajka]

Description:

This PR introduces a detailed data format specification for processed data.

• Based on OceanSITES 1.4 with some enhancements/deviations
• Incorporates OG1 (OceanGliders) patterns for contributor metadata
• Maintains CF conventions and ACDD compliance
• Enhanced vocabulary requirements for interoperability
• ORCID integration for persistent researcher identification
• OceanSITES QC flag system, but with notes of deviations from IOC
• Specifications for file naming conventions following OceanSITES
• Dimensions: Uses N_LEVELS instead of DEPTH (more aligned with CCHDO)
• Units: UDUNITS-2 compliance with oceanographic additions (sverdrup instead of Sv, to distinguish from sievert)
• Time format: OG1 compact format (YYYYmmddTHHMMss instead of YYYY-MM-DDThh:mm:ssZ

Checklist:

• I have followed the coding conventions.
• I have updated or added tests to cover my changes.
• I have updated the documentation if needed.
• I have run pytest to check that all tests pass.
• I have run pre-commit run --all-files to lint and format the code.