Updated to use Tensorflow2

This MR constitutes a major overhaul. The following changes have been made:

1. Tensorflow code samples now use Tensorflow2
2. Removed all Caffe samples and corresponding resources
3. Updated the tutorial in general to include all the new machines.

caffe/lenet_python/lenet_auto_solver.prototxt

-# The train/test net protocol buffer definition
-train_net: "lenet_auto_train.prototxt"
-test_net: "lenet_auto_test.prototxt"
-# test_iter specifies how many forward passes the test should carry out.
-# In the case of MNIST, we have test batch size 100 and 100 test iterations,
-# covering the full 10,000 testing images.
-test_iter: 100
-# Carry out testing every 500 training iterations.
-test_interval: 500
-# The base learning rate, momentum and the weight decay of the network.
-base_lr: 0.01
-momentum: 0.9
-weight_decay: 0.0005
-# The learning rate policy
-lr_policy: "inv"
-gamma: 0.0001
-power: 0.75
-# Display every 100 iterations
-display: 100
-# The maximum number of iterations
-max_iter: 10000
-# snapshot intermediate results
-snapshot: 5000
-snapshot_prefix: "snapshots/lenet"