Support table-based configuration of blocked-by relations

[PerMalmberg]

Something like this:

{
    "--primary": [0, 1, 1],
    "--foo":     [1, 0, 0],
    "--bar":     [0, 0, 1]
}

X-wise, columns are to be read as the same index in rows, i.e. first column is "primary"

Example means that --primary and --bar are mutually exclusive (even if only one of them would have had a 1 in the column) and --foo can't be used with --primary.