Create customCAFEAdditionalData metadata block with CCH Terms field

[Saixel]

What this PR does / why we need it:

This PR creates a new custom metadatablock customCAFEAdditionalData, which includes the CCH Terms field.

Which issue(s) this PR closes:

• Closes Implement Dropdown Selector for NIH Controlled Vocabulary in Keywords #267

Additional documentation:

[jggautier]

Hi @Saixel. I looked at the screenshots and the TSV file. From that, the only change I'd suggest is adding a description of the field in the TSV file's "description" column so that something appears when folks hover over or click on the blue question mark next to the CCH Term field label. There's more guidance about the Dataverse metadata text guidelines about tooltips.

[jggautier]

Thanks for adding the description for the field's tooltip. The only thing I think needs to be changed is the period at the end of the sentence. Could you delete the period? Or would you mind if I deleted it?

[jggautier]

Thanks @Saixel. After our conversation on Slack I deleted the period at the end of the description.