Fix and enhance TIMIT recipe

[flyingleafe]

• Actually touch .completed detector file to avoid re-downloading
• Actually use multiple processes during preparation when num_jobs > 1
• Fix the paths to audio files and transcriptions in the unpacked folder (add data subdirectory)
• Use full text as transcription on SupervisionSegment level; add word and phoneme transcriptions as alignment layers.
• Provide info about speaker's gender explicitly to SupervisionSegment
• Better progress reporting via tqdm

[pzelasko]

@luomingshuang could you take a look? I think you were building the Icefall recipe for TIMIT, would be great if you checked this PR doesn't break it.

[luomingshuang]

Ok, I will have a check for it.

[flyingleafe]

@luomingshuang bump, all good?

[desh2608]

@luomingshuang do you think this is good to merge?

[luomingshuang]

I am having a check for it.

[luomingshuang]

Well, I think this PR is ready to MERGE. It adds some functions for alignment.

[pzelasko]

Thanks for the contribution @flyingleafe and for the help in reviewing @luomingshuang!