Do not expose module IPsec(IKE) API from frameworks

Module IPsec(IKE) will not be in bootclasspath or expose API
from frameworks/base anymore. Instead it will be built as a
java_sdk_library and expose APIs under its own directory.

This commit:
- Removes API from frameworks/base
- Adds ike to FrameworksNetTests manifest so that VpnTest is
  able to load it.

Bug: 145995723
Test: build, flash, boot
Test: atest FramewokrsIkeTests (passed)
Test: m mts && mts-tradefed run mts-ipsec (passed)
Test: manually tested that FrameworksNetTests can use ike.jar
Change-Id: I37ba02eb3003ea28e66f50ca0b612597ef48f6d5