add doc for missing OMV core plugins (#69)

Co-authored-by: Volker Theile <votdev@gmx.de>

plugins.rst

@@ -22,11 +22,15 @@ Overview
 
 The following is the list of official plugins by |omv|.
 
-* **ClamAV**: Provides antivirus scan for folders.
+* **ClamAV**: Provides Clam AntiVirus (ClamAV). It is a free software, cross-platform and open-source antivirus software toolkit able to detect many types of malicious software, including viruses
+* **Diskstats**: Complementary plugin to extend system statistics collection by adding I/O statistic graphs.
 * **Forked-daap**: Provides a daap protocol music server.
 * **LVM2**: LVM managing. Create volume groups and logical partitions.
-* **Diskstats**: Complementary plugin to extend current system statistics collection by adding iostats graphs.
 * **NUT**: Controlling and configuring UPS. The driver support is based on NUT.
+* **Shairport**: Provides Airtunes emulator. Stream music wirelessly to your iPod/iPad/iPhone/iTunes.
+* **ShareRootFs**: Provides shared directories on root file system.
+* **SNMP**: Provides Simple Network Management Protocol (SNMP). SNMP is an Internet Standard protocol for collecting and organizing information about managed devices on IP networks.
+* **TFtp**: Provides Trivial File Transfer Protocol (TFTP). TFTP is a simple lockstep File Transfer Protocol which allows a client to get a file from or put a file onto a remote host.
 * **USB Backup**: Backup internal data to external disks on scheduled basis or on plug drive event.
 
 .. _plugin_3rd_party: