Add snip_momentum structured pruning example with 80% sparsity ratio

[ftian1]

This PR is used to demonstrate the functionality of snip_momentum structured pruning algo implemented in here.

User can reproduce below result by running source ./bash_script/pruning_sparse_snip_momentum.sh with the PR mentioned at above.

pattern	sparsity ratio	pruning method	epochs	acc & mm-acc
1x1	80%	DeepSpeed L1	2	0.8113/0.822
1x1	80%	Snip_momentum	2	0.8176/0.822
4x1	80%	snip_momentum	10	0.8248/0.8305