Silence curl output in pia-wg.sh

[bwitt]

Silence wget output in pia-wg.sh by adding --silent --show-error where stdout goes to the terminal, and -s where it's being read.

Also added an echo to get the output to the terminal to look better.

Fixes #10

$ ./pia-wg.sh -c 
Generating new private key
Setting default location: any
Setting default wireguard interface name: pia
Cannot read '/home/bwitt/.config/pia-wg/pia-wg.conf', generating a default one
Please enter your privateinternetaccess.com username: pxxxxxxx
Config saved
Fetching new generation server list from PIA
Fetching PIA self-signed RSA certificate from github
Selecting server 2 from 2 choices
A new auth token is required.
Your password will NOT be saved.
Please enter your privateinternetaccess.com password for pxxxxxxx: 
Your password has been forgotten, please edit /home/bwitt/.config/pia-wg/pia-wg.conf and set PIA_PASSWORD if you wish to store it permanently.
Functional DNS is no longer required.
If you're setting up in a region with heavy internet restrictions, you can disable your alternate VPN or connection method now