The static validate() method an PROXY_* constants in Proxy are
used by both module and Settings. After Proxy is moving into
connectivity module, Setting will not able to access them.
Thus, move them to ProxyUtils in net shared lib.
Bug: 172183305
Test: atest FrameworksNetTests
Test: atest CtsNetTestCases:ProxyInfoTest
Change-Id: I02c88aeaeb53d62b87a42a2d8ead9b140b054650
Files that are planned to be part of the connectivity module are grouped
in packages/Connectivity, so they can be built separately and moved in
one operation with their history into packages/modules/Connectivity.
This places the files in the existing framework-connectivity-sources
filegroup instead of the current framework-core-sources filegroup. Both
are used the same way in framework-non-updatable-sources.
Bug: 171540887
Test: m
Change-Id: I62d9d91574ace6f5c4624035d190260c3126b91e
