add system info page for admin user to diagnose the system

unify portal logout url to /user/logout

add query function for portal server config page

Add getProperty with transform function

fix the situation when some public app namespace is deleted and recreated in another app

allow admin to create private namespace by default

update apollo logo

merge 1.x to master

support setting apollo system properties via application.properties

support setting apollo.meta, app.id, apollo.cacheDir and apollo.cluster from spring boot configuration files, e.g. application.properties, bootstrap.properties, etc