Remove mention of quickstart from package based stellar-core install …

…instructions (#259)

docs/run-core-node/installation.mdx

@@ -45,8 +45,6 @@ If you are using Ubuntu 18.04 LTS or later, we provide the latest stable release
 
 You may choose to install these packages individually, which offers the greatest flexibility but requires **manual** creation of the relevant configuration files and configuration of a **PostgreSQL** database.
 
-Most people, however, choose to install the [stellar-quickstart](https://github.com/stellar/packages/blob/master/docs/quickstart.md) package which configures a **Testnet** `stellar-core` and `stellar-horizon` both backed by a local PostgreSQL database. Once installed you can easily modify either the Stellar Core configuration if you want to connect to the public network.
-
 ## Installing from source
 
 See the [install from source](https://github.com/stellar/stellar-core/blob/master/INSTALL.md) for build instructions.