scripted-diff: move settings to common namespace

-BEGIN VERIFY SCRIPT-
sed -i 's/namespace\ util/namespace\ common/g' src/common/settings.cpp src/common/settings.h
sed -i 's/util\:\:GetSetting/common\:\:GetSetting/g' $( git grep -l 'util\:\:GetSetting')
sed -i 's/util\:\:Setting/common\:\:Setting/g' $( git grep -l 'util\:\:Setting')
sed -i 's/util\:\:FindKey/common\:\:FindKey/g' $( git grep -l 'util\:\:FindKey')
sed -i 's/util\:\:ReadSettings/common\:\:ReadSettings/g' $( git grep -l 'util\:\:ReadSettings')
sed -i 's/util\:\:WriteSettings/common\:\:WriteSettings/g' $( git grep -l 'util\:\:WriteSettings')
-END VERIFY SCRIPT-

src/interfaces/chain.h

@@ -300,17 +300,17 @@ public:
     virtual int rpcSerializationFlags() = 0;
 
     //! Get settings value.
-    virtual util::SettingsValue getSetting(const std::string& arg) = 0;
+    virtual common::SettingsValue getSetting(const std::string& arg) = 0;
 
     //! Get list of settings values.
-    virtual std::vector<util::SettingsValue> getSettingsList(const std::string& arg) = 0;
+    virtual std::vector<common::SettingsValue> getSettingsList(const std::string& arg) = 0;
 
     //! Return <datadir>/settings.json setting value.
-    virtual util::SettingsValue getRwSetting(const std::string& name) = 0;
+    virtual common::SettingsValue getRwSetting(const std::string& name) = 0;
 
     //! Write a setting to <datadir>/settings.json. Optionally just update the
     //! setting in memory and do not write the file.
-    virtual bool updateRwSetting(const std::string& name, const util::SettingsValue& value, bool write=true) = 0;
+    virtual bool updateRwSetting(const std::string& name, const common::SettingsValue& value, bool write=true) = 0;
 
     //! Synchronously send transactionAddedToMempool notifications about all
     //! current mempool transactions to the specified handler and return after

src/interfaces/node.h

@@ -103,14 +103,14 @@ public:
     virtual bool isSettingIgnored(const std::string& name) = 0;
 
     //! Return setting value from <datadir>/settings.json or bitcoin.conf.
-    virtual util::SettingsValue getPersistentSetting(const std::string& name) = 0;
+    virtual common::SettingsValue getPersistentSetting(const std::string& name) = 0;
 
     //! Update a setting in <datadir>/settings.json.
-    virtual void updateRwSetting(const std::string& name, const util::SettingsValue& value) = 0;
+    virtual void updateRwSetting(const std::string& name, const common::SettingsValue& value) = 0;
 
     //! Force a setting value to be applied, overriding any other configuration
     //! source, but not being persisted.
-    virtual void forceSetting(const std::string& name, const util::SettingsValue& value) = 0;
+    virtual void forceSetting(const std::string& name, const common::SettingsValue& value) = 0;
 
     //! Clear all settings in <datadir>/settings.json and store a backup of
     //! previous settings in <datadir>/settings.json.bak.