v0.9.1 Installation Enhancement

Update package version:

• PostgreSQL 13.3
• Grafana 7.5.6

Add configure support.

Now install pigsty with 3 steps: download, configure and install:

curl -fsSL https://github.com/Vonng/pigsty/releases/download/v0.9.1/pigsty.tgz | gzip -d | tar -xC ~; cd ~/pigsty
./configure
make install

WoW! just like old time!