Clean metadata examples

[perolavsvendsen]

Metadata examples needs cleaning up.

• [x] Remove redundant comments
• [ ] Remove restart_from (currently not used)
• [x] Add file.size
• [x] Add multi-level fmu.realization.parameters
• [x] Add table example
• [ ] Remove data.properties? (Not used)
• [ ] Remove data.grid_model (Not used)
• [x] Remove realization.jobs (Not used)

[perolavsvendsen]

Keep restart_from and grid_model - part of schema.

[perolavsvendsen]

Keep properties - use for tables (and for surfaces in the future?)