* feat(plugin): Add filestore Windows implementation
* Define UA_DT_REG and UA_DT_DIR
* Remove build flag and use __linux__ or UA_ARCHITECTURE_WIN32 in places which used to check only for __linux__
We want to have the same default for client and server. So we get less
trouble with reusing certificates. Before we had to manually adjust the
client URI to say "server". That's not good...