UPD Provider's fault
I think I have read all the instructions and have done everything I could, but it still doesn't work :(
List of things I have done so far:
in httpd.conf file of the Apache server:
ServerName 192.168.0.102:8080
...
# onlineoffline tag - don't remove
Require all granted
...
Listen 0.0.0.0:8080
Listen [::0]:8080
Then I have the following result:
C:\Users\Sam>netstat -na | find ":8080"
TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING
TCP [::]:8080 [::]:0 LISTENING
So, I guess, no firewall interruptions..
Then I have forwarded the thing in my TL-WR842ND router as follows:
In DHCP I set static local IP of 192.168.0.102 to my MAC and forwarded port 8080 to that IP. Then I rebooted the router but the port is still closed.
I can access WAMP though localhost:8080, through 192.168.0.102:8080, but cannot access remotely through the public IP. I also tried to set DMZ to 192.168.0.102 but that also had no impact. I called my provider and they said that they allow port forwarding and the problem must be on my side. pls help :(
Turns out, I have a common IP address with multiple other users and I have to pay extra to my provider in order to be able to expose services to the outside. I believe that is called a non-routable IP address.
You can read about it here