Override Network Manager DNS

Sometimes, you just want to set DNS Servers the old fashioned way, but Linux's Network Manager won't let you.

Two ways to fix this:
1. Edit NetworkManager.conf
Edit /etc/networkmanager/NetworkManager.conf setting dns=none
Then edit /etc/resolv.conf to be whatever you want.. NetworkManager will leave it alone. 
Am currently preferring/using this one, for no particular reasons. 

2.  Symlink
Seems at least in my testing, Network Manager will not override a symlink.  
This is RedHat's official solution, but works on Armbian/Debian. YMMV.   
Create a file like /etc/resolv.manual.conf with what you need. like:
nameserver 8.8.8.8
nameserver 192.168.1.2

Then remove the current /etc/resolv.conf and symlink it. 
rm /etc/resolv.conf
ln -s /etc/resolv.manual.conf /etc/resolv.conf