Chore: customize round "option" name

[kittybest]

Prerequisites

Please answer the following question for yourself before submitting a feature request.

• I checked to make sure that this request has not already been filed

Motivation

See discussion in #620

Details

Not all round vote for "projects", sometimes they could be "dashboard", "policy", or even just an "option".
We could allow the coordinator to customize the name of it in the round metadata.

So we need to

• update the upload-round-metadata function
• update the interface display

Make sure that you have reviewed MACI's Contributor Guidelines

[mabsattar]

Hi @kittybest , can you assign me this, i'd like to work on it.