abstracting out the data gathering logic for data pipeline

Package.swift

...s/SwiftNLP/1. Data Collection/ReadRedditCommentFile.swift

Sources/SwiftNLP/1. Data Collection/RedditComment.swift

Sources/SwiftNLP/1. Data Collection/RedditSubmission.swift

...wiftNLP/1. Data Collection/readRedditSubmissionData.swift

Tests/SwiftNLPTests/NLPLoadJsonTests.swift

Tests/SwiftNLPTests/Resources/RedditComment/RC_2014-05.json

Tests/SwiftNLPTests/Resources/RedditComment/RC_2017-08.json

Tests/SwiftNLPTests/Resources/RedditComment/RC_2020-11.json

.../SwiftNLPTests/Resources/RedditSubmission/RS_2015-10.json

.../SwiftNLPTests/Resources/RedditSubmission/RS_2017-05.json

.../SwiftNLPTests/Resources/RedditSubmission/RS_2018-03.json

.../SwiftNLPTests/Resources/RedditSubmission/RS_2021-11.json

Tests/SwiftNLPTests/TestUtil/LoadTestJson.swift