Convert ProjectMetadata class to have ruby attributes instead of being based on a hash

[carolyncole]

What maintenance needs to be done?

Utilizing a hash is hard to test and unreliable. We would like the class to explicitly know about all attributes needed and be able to validate those attributes.

We also want the Metadata class to be able to be used to generate the json for the project.to_json and the jsonb for the database save.

Level of urgency

• [ ] High
• [x] Moderate
• [ ] Low

Acceptance criteria

• [ ] Add a save_to_mediaflux method ProjectMetadata.new(my_project).save_to_mediaflux
• [ ] Add ruby class properties for the metadata json values of the project
• [ ] Add a test that contacts mediaflux to replace the metadata for a project that has a mediaflux id by calling save_to_mediaflux
• [ ] All other methods will not be touched
• [ ] Clean up the code to call save_to_mdiaflux instead of ProjectMediaflux#update and remove the method in ProjectMediaflux

Implementation notes, if any

[carolyncole]

Hey team! Please add your planning poker estimate with Zenhub @hectorcorrea @JaymeeH @jrgriffiniii @kelynch @leefaisonr