Use more C++17 features

Mainly structured bindings, inline variables, and class template
argument deduction, plus many more smaller things.

Change-Id: I810d17e0adb470426e4e30c898e03b3140ad052f
diff --git a/daemon/rib/readvertise/host-to-gateway-readvertise-policy.cpp b/daemon/rib/readvertise/host-to-gateway-readvertise-policy.cpp
index 89f11fd..5aa6e3b 100644
--- a/daemon/rib/readvertise/host-to-gateway-readvertise-policy.cpp
+++ b/daemon/rib/readvertise/host-to-gateway-readvertise-policy.cpp
@@ -33,8 +33,8 @@
 namespace nfd {
 namespace rib {
 
-static const name::Component IGNORE_COMPONENT("nrd");
-static const time::seconds DEFAULT_REFRESH_INTERVAL = 25_s;
+const name::Component IGNORE_COMPONENT("nrd");
+const time::seconds DEFAULT_REFRESH_INTERVAL = 25_s;
 
 HostToGatewayReadvertisePolicy::HostToGatewayReadvertisePolicy(const ndn::KeyChain& keyChain,
                                                                const ConfigSection& section)