vfs.dir.size metric support to agent2 on windows
* commit 'c7b3eed670171325bca880c57e2a15a0d9616c2b':
.......... [DEV-1434] fixed warning of windows agent2 compilation
.......... [DEV-1434] fixed zabbix_agentd compiling
.......... [DEV-1434] added vfs.dir.* metric support
.......... [DEV-1434] fixed windows dns metrics
.......... [DEV-1434] add net.dns, net.dns.record supoprt via C code
.......... [DEV-1434] moved dns metrics to separate file
(cherry picked from commit 322a38b03c3217a832bef2c0186306a9bd964b2a)