add anomaly-detection-hd

[Herald-of-Aurora]

This is the revised pr of intel-analytics/analytics-zoo#595

[songhappy]

1. remove data
2. add scripts in the notebook as other notebook (https://github.com/intel-analytics/analytics-zoo/blob/master/apps/anomaly-detection/anomaly-detection-nyc-taxi.ipynb) to get download data
3. add more definition of anomalies in both README and notebook

[shane-huang]

Revise the last part, namely the block [12] chart. Replace it with a demostration of outlier dimensions can be detected. Specifically,

1. Plot the recostruction errors of points 50, 121, 350, 572, 669 in each dimension as in block [46] of https://github.com/edouardfouche/neural-based-outlier-discovery/blob/master/autoencoder-keras.ipynb
2. plot the above points in block in subspace [30,31,32] and marked them as red as in block [44] in https://github.com/edouardfouche/neural-based-outlier-discovery/blob/master/autoencoder-keras.ipynb

[shane-huang]

1. Change block[14] to plot the point 204 in 2d subspace [22,23].
2. Add one more plot at then end, plot points 21, 204, 212, 100, 122, 19, 232 and 71 in 3d subspace [7,8,9]