check consistency in the names of the q variables

[rcabanasdepaz]

It could happen that the user wrongly specified the variables names in the Q model.
At least, a warning should be shown. For instance, consider the following example where the qw0 should be named w0

@inf.probmodel
def linear_reg(d):
    w0 = inf.Normal(0, 1, name="w0")
    w = inf.Normal(0, 1, batch_shape=[d,1], name="w")

    with inf.datamodel():
        x = inf.Normal(5, 2, batch_shape=d, name="x")
        y = inf.Normal(w0 + x @ w, 1.0, name="y")


@inf.probmodel
def qmodel(d):
    qw0_loc = inf.Parameter(0., name="qw0_loc")
    qw0_scale = tf.math.softplus(inf.Parameter(1., name="qw0_scale"))
    qw0 = inf.Normal(qw0_loc, qw0_scale, name="qw0")

    qw_loc = inf.Parameter(tf.zeros([d,1]), name="qw_loc")
    qw_scale = tf.math.softplus(inf.Parameter(tf.ones([d,1]), name="qw_scale"))
    qw = inf.Normal(qw_loc, qw_scale, name="w")