Make `position.tier` to `position.tiers`

[karnikaavelumani]

What happened?

Allow board members to hold multiple positions on the board. This will allow their image to show up on multiple teams to show their contribution.

Current:

"S23": {
        "title": "Vice President/Webmaster",
        "tier": 1
      }

Requested:

"S23": [ { "title": "Vice President", "tier": 1 }, {"title": "Webmaster", "tier": 2]