Remove Debian 7 from installation notes and system req.

[ci skip]

docs/installation/packaged/debian-7/README.md

@@ -1,36 +0,0 @@
-### Steps to install OpenProject on Debian 7 (Wheezy)
-
-All steps need to be run as `root`.
-
-**1. Import the packager.io repository signing key**
-
-Import the PGP key used to sign our packages. Since we're using the _packager.io_ platform to distribute our packages, both package source and signing key are tied to their service.
-
-```bash
-wget -qO- https://dl.packager.io/srv/opf/openproject-ce/key | sudo apt-key add -
-```
-
-**2. Install apt-https suppport**
-
-Since we only provide https package sources, you may need to install `apt-transport-https` as a preliminary step.
-
-```bash
-apt-get install apt-transport-https
-```
-
-
-**3. Add the OpenProject package source**
-
-```
-sudo wget -O /etc/apt/sources.list.d/openproject-ce.list \
-  https://dl.packager.io/srv/opf/openproject-ce/stable/7/installer/debian/7.repo
-```
-
-**4. Install the OpenProject Community Edition package**
-
-Using the following commands, apt will check the new package source and install the package and all required dependencies.
-
-```bash
-apt-get update
-apt-get install openproject
-```

docs/installation/system-requirements.md

@@ -16,7 +16,6 @@ provide any official support for them.
 | Distribution (64 bits only)     | Identifier   | init system |
 | :------------------------------ | :----------- | :---------- |
 | CentOS/RHEL 7.x                 | centos-7     | systemd     |
-| Debian 7 Wheezy                 | debian-7     | sysvinit    |
 | Debian 8 Jessie                 | debian-8     | systemd     |
 | Debian 9 Stretch                | debian-9     | systemd     |
 | Suse Linux Enterprise Server 11 | sles-11      | sysvinit    |