update for 'src' column

[SinghGursimran]

update for 'src' column

#418

For Testing:

import io.archivesunleashed._
import io.archivesunleashed.df._

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.webgraph()
			.select($"src")
			.keepUrlPatternsDF(Set(".*index.*".r))
			.show(10,false)

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.webgraph()
			.select($"src")
			.discardUrlPatternsDF(Set(".*images.*".r))
			.show(10,false)

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.webgraph()
			.select($"src")
			.keepUrlsDF(Set("http://www.archive.org/","http://www.archive.org/index.php"))
			.show(10,false)

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.webgraph()
			.select($"src")
			.discardUrlsDF(Set("http://www.archive.org/","http://www.archive.org/index.php"))
			.show(10,false)

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.imagegraph()
			.select($"src")
			.keepDomainsDF(Set("www.archive.org"))
			.show(10,false)

RecordLoader.loadArchives("./src/test/resources/arc/example.arc.gz",sc)
			.webgraph()
			.select($"src")
			.discardDomainsDF(Set("www.archive.org"))
			.show(10,false)

[codecov]

Codecov Report

Merging #424 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #424   +/-   ##
=======================================
  Coverage   78.15%   78.15%           
=======================================
  Files          41       41           
  Lines        1584     1584           
  Branches      299      299           
=======================================
  Hits         1238     1238           
  Misses        218      218           
  Partials      128      128

[ruebot]

@SinghGursimran nice! I did a hasColumn function for a similar solution in twut. Can we get a test update too?

@lintool @ianmilligan1 do either of you see a use case for filtering on dest or image_url? Or is src, and url good enough here? If we add dest or image_url, we'd probably need to change the implementation to pass the column name as well.

[ruebot]

@SinghGursimran based on the new related issue (#425) let's just worry about getting the tests updated here, and don't worry about dest and image_url for now since the implementation of #425 would resolve that.

I'm running the right now on the entire GeoCities dataset for other project, and everything appears to be running smoothly 🙌