Add javadoc link to WPILib docs and oracle java docs.

[thenetworkgrinch]

Adds javadocs external links for javadocs generation. It may be worthwhile to add javadocs.destinationDir = new File("$buildDir/repos/") that way javadocs is also exported to the maven repo for an easy hosting solution.

[sciencewhiz]

Does this break during beta if the vendor is using a new API that isn't in the WPILib release docs?

[thenetworkgrinch]

I have no clue, i was able to compile it just fine when i tested it. Javadocs usually doesnt link to anything that it cant find, so i imagine it would just do the class name with no external link like it normally does without it.

[thenetworkgrinch]

To answer your question, it appears if something doesnt exist it just wont link to it. See here as an example.

https://pathplanner.dev/api/java/com/pathplanner/lib/util/DriveFeedforwards.html#%3Cinit%3E(edu.wpi.first.units.measure.LinearAcceleration[],edu.wpi.first.units.measure.Force[],edu.wpi.first.units.measure.Current[],edu.wpi.first.units.measure.Force[],edu.wpi.first.units.measure.Force[])