Add filtering of columns for variant table

[sambaxter]

Can the headers of the variant table sort the columns?

[nawatts]

Is the request here to be able to filter which variants are shown in the table? Or to sort the table by different columns?

[sambaxter]

I was originally thinking to filter which variants are shown in the table but sorting on each column is probably easier to implement. If that is the case I think we can just add sorting to each column

[nawatts]

As of 38c7fef2d4385986d2e1ac67ae78f6879b85097a, the variant table should be sortable by any column (by clicking the column header).

[nawatts]

Allowing sorting the list by each column satisfies this.