List all projects.

def projects(accountable):
    """
    List all projects.
    """
    projects = accountable.metadata()['projects']
    headers = sorted(['id', 'key', 'self'])
    rows = [[v for k, v in sorted(p.items()) if k in headers] for p in projects]
    rows.insert(0, headers)
    print_table(SingleTable(rows))