tests: add test os-release files

tests/etc/ALT/etc/os-release

+NAME="ALT SPWorkstation"
+VERSION="8.4"
+ID=altlinux
+VERSION_ID=8.4
+PRETTY_NAME="ALT 8 SP Workstation (cliff)"
+ANSI_COLOR="1;33"
+CPE_NAME="cpe:/o:alt:spworkstation:8.4"
+HOME_URL="https://basealt.ru/"
+BUG_REPORT_URL="https://bugs.altlinux.org/"

tests/etc/ALTMED/etc/altlinux-release

+ALT MED72

tests/etc/ALTMED/etc/os-release

+#
+# Examples:
+#
+# DISTRIB_ID - single word, ID of DISTRIBUTOR
+# DISTRIB_RELEASE="5.0.0"
+# DISTRIB_CODENAME="Lycoris Radiata"
+# DISTRIB_DESCRIPTION="ALT Linux Sisyphus (20081222)"
+# DISTRIB_DESCRIPTION="ALT Linux 1.0.0 Server Light r1 (Lycoris Radiata)"
+NAME="ALT MED72"
+VERSION="8.3 ()"
+ID=altlinux
+VERSION_ID=8.3
+PRETTY_NAME="ALT MED72 ()"
+ANSI_COLOR="1;33"
+CPE_NAME="cpe:/o:alt linux:med72:8.3"
+HOME_URL="http://basealt.ru/"
+BUG_REPORT_URL="https://bugs.altlinux.org/"

tests/etc/ALTServer/etc/os-release

+NAME="ALT Server"
+VERSION="10.0"
+ID=altlinux
+VERSION_ID=10.0
+PRETTY_NAME="ALT Server 10.0 (FalcoRusticolus)"
+ANSI_COLOR="1;33"
+CPE_NAME="cpe:/o:alt:server:10.0"
+BUILD_ID="ALT Server 10.0"
+HOME_URL="https://basealt.ru/"
+BUG_REPORT_URL="https://bugs.altlinux.org/"

tests/etc/MESh/etc/os-release

+NAME="MESh"
+VERSION="School 830"
+ID=kometa
+VERSION_ID=10
+PRETTY_NAME="KOMETA School 830"
+ANSI_COLOR="1;33"
+CPE_NAME="cpe:/o:alt:kometa:p10"
+LOGO=kometa