Add service proxy

This adds a service proxy based on nfproxy and changes to the service IP allocation to make it work.
Also adds support for masquerading outbound traffic for outbound network connectivity.

Test Plan:
Currently manually tested by creating an alpine pod and running 'apk add curl && curl -k https://192.168.188.1:443/'.
Will be covered later by CTS.

Bug: T810

X-Origin-Diff: phab/D580
GitOrigin-RevId: cace863fd8c2f045560f8abf84c40cc77bc275d4
diff --git a/core/internal/network/BUILD.bazel b/core/internal/network/BUILD.bazel
index 9eefc1b..ad7de74 100644
--- a/core/internal/network/BUILD.bazel
+++ b/core/internal/network/BUILD.bazel
@@ -8,6 +8,8 @@
     deps = [
         "//core/internal/common/supervisor:go_default_library",
         "//core/internal/network/dhcp:go_default_library",
+        "@com_github_google_nftables//:go_default_library",
+        "@com_github_google_nftables//expr:go_default_library",
         "@com_github_vishvananda_netlink//:go_default_library",
         "@org_golang_x_sys//unix:go_default_library",
         "@org_uber_go_zap//:go_default_library",