Replace reshaping workaround with ReshapePorts

[mathisrichter]

In the absence of ReshapePorts in Lava, we have implemented reshaping with dedicated Reshape Processes (ReshapeBool, ReshapeInt) and changed the implementation of the connect() function to insert these Processes:
Population (Source) -> ReshapeBool -> Dense -> ReshapeInt -> Population (Destination)

Once ReshapePorts are available, use them and remove the Reshape Processes.

1. In connect.py, replace

    # make connections from the source port to the connections process
    # TODO (MR) workaround in absence of ReshapePorts
    con_ip = connections.s_in
    rs1 = ReshapeBool(shape_in=src_op.shape, shape_out=con_ip.shape)
    src_op.connect(rs1.s_in)
    rs1.s_out.connect(con_ip)

    # make connections from the connections process to the destination port
    # TODO (MR) workaround in absence of ReshapePorts
    con_op = connections.a_out
    rs2 = ReshapeInt(shape_in=con_op.shape, shape_out=dst_ip.shape)
    con_op.connect(rs2.s_in)
    rs2.s_out.connect(dst_ip)

by

    # make connections from the source port to the connections process
    src_op_flat = src_op.reshape(connections.in_ports.s_in.shape)
    src_op_flat.connect(connections.in_ports.s_in)

    # make connections from the connections process to the destination port
    con_op = connections.out_ports.a_out.reshape(dst_ip.shape)
    con_op.connect(dst_ip)

2. In test_connect.py, replace

        # check whether 'source' is connected to 'connections'
        src_op = source.out_ports.s_out
        con_ip = connections.in_ports.s_in
        # TODO (MR): remove this after switching to Reshape ports
        rs1_op = src_op.get_dst_ports()[0].process.out_ports.s_out
        self.assertEqual(rs1_op.get_dst_ports(), [con_ip])
        self.assertEqual(con_ip.get_src_ports(), [rs1_op])

        # check whether 'connections' is connected to 'target'
        con_op = connections.out_ports.a_out
        dst_op = destination.in_ports.a_in
        # TODO (MR): remove this after switching to Reshape ports
        rs2_op = con_op.get_dst_ports()[0].process.out_ports.s_out
        self.assertEqual(rs2_op.get_dst_ports(), [dst_op])
        self.assertEqual(dst_op.get_src_ports(), [rs2_op])

by

        # check whether 'source' is connected to 'connections'
        src_op = source.out_ports.s_out
        con_ip = connections.in_ports.s_in
        self.assertEqual(src_op.get_dst_ports(), [con_ip])
        self.assertEqual(con_ip.get_src_ports(), [src_op])

        # check whether 'connections' is connected to 'target'
        con_op = connections.out_ports.a_out
        dst_op = destination.in_ports.a_in
        self.assertEqual(con_op.get_dst_ports(), [dst_op])
        self.assertEqual(dst_op.get_src_ports(), [con_op])

3. Remove directories lava/lib/dnf/connect/reshape_* including all content.

[mathisrichter]

Fixed by #31