elapsed_time_total is misleading

[SebieF]

Currently, the elapsed_time_total variable in the output file indicates the value of the training time in seconds. It should be changed to indicate the complete time interval from start of the program to finish, and be supported by other variables for further information:

• elapsed_time_embedding: Time for embedding including loading the embeddings file
• elapsed_time_training: Time for training all splits of the model
• elapsed_time_testing: Time for running the trained model on the test file