MD Settings: Internet: Add/fix remaining policy items
This CL:
* Adds a policy indicator to cr-network-list-item
* Adds a policy indicator in the top line of the detailed view
* Replaces the proxy indicator for extensions with
extension-controlled-indicator
* Includes a small amount of additional layout cleanup
BUG=
668228
For existing I18nBehavior in cr_network*:
NOPRESUBMIT=true
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
Committed:
https://crrev.com/814ce188d59121f142274c44629521d99d27c570
Cr-Commit-Position: refs/heads/master@{#436403}