Add aerospace_engineering_corpus dataset to nltk_data

[jason-sloan]

A 170-item corpus for aerospace engineering terminology. There are some phrases, but most are single words.

[alvations]

Please avoid any zip file for now, list them here and checkin text file and we'll check the content in the plain text and zip it up ourselves and push it into PR, we can no longer open or check zip files directly due to too many securities breaches in datasets.

Also, no promises that any new datasets will make it into the library, since NLTK is in maintenance mode.

[jason-sloan]

Thanks alvations.

[ekaf]

A small database like this doesn't fit well in NLTK. It is not a corpus, but a single word list. Since it has no purpose nor corpus reader, users wouldn't know what to do with it.
It seems better suited as an addition to a lexical resource like Wikipedia or the Open English Wordnet, but they would likely request more meat, such as definitions or related words.