API refactoring

[tzaeschke]

Clean up API:

• Return ScionSocketAddress
• Deduplicate address info ScionScoketAddress <-> path
• Remove ResponseAddress type from API
• ....

[codecov]

Codecov Report

Attention: Patch coverage is 95.00000% with 1 line in your changes missing coverage. Please review.

Files	Coverage Δ	Complexity Δ
src/main/java/org/scion/jpan/Path.java	64.28% <100.00%> (+1.78%)	6.00 <4.00> (+1.00)
...main/java/org/scion/jpan/ScionDatagramChannel.java	82.72% <100.00%> (ø)	24.00 <0.00> (ø)
.../main/java/org/scion/jpan/ScionDatagramSocket.java	54.96% <100.00%> (-0.18%)	57.00 <0.00> (ø)
.../scion/jpan/internal/SelectingDatagramChannel.java	83.33% <100.00%> (ø)	8.00 <0.00> (ø)
...c/main/java/org/scion/jpan/ScionSocketAddress.java	87.50% <87.50%> (ø)	4.00 <4.00> (?)