Decide data model

[epijim]

Currently we have from the old site some questionable data models that need tidying up.

[epijim]

first pass in #2

[harveyl888]

Some thoughts on data.

• Data validation used for times in google sheet. May be better to ditch this approach moving forward.
• For team sheet we should include a column to tag former members (currently an additional sheet called old_team is used.
• For team we should also include an option to include photos other than those from gravatar. We did this for APAC team. We can also include APAC team (and other teams via tagging).
• workshops sheet can be dropped (it was used for workshop registration on old site).