Move installation files into installation folder for 2.2 reorg.

diff --git a/server_installation.txt b/installation/server_installation.txt
similarity index 100%
rename from server_installation.txt
rename to installation/server_installation.txt

diff --git a/server_upgrade.txt b/installation/server_upgrade.txt
similarity index 100%
rename from server_upgrade.txt
rename to installation/server_upgrade.txt

diff --git a/system_requirements.txt b/installation/system_requirements.txt
similarity index 100%
rename from system_requirements.txt
rename to installation/system_requirements.txt