Collector documentation (#113)

* Initial draft of collector documentation

* Add docs for all collectors

* Update main README with links to docs

* Fix link syntax

docs/README.md

@@ -0,0 +1,29 @@
+# Documentation
+This directory contains documentation of the collectors in the WMI exporter, with information such as what metrics are exported, any flags for additional configuration, and some example usage in alerts and queries.
+
+# Collectors
+- [`ad`](collector.ad.md)
+- [`cpu`](collector.cpu.md)
+- [`cs`](collector.cs.md)
+- [`dns`](collector.dns.md)
+- [`hyperv`](collector.hyperv.md)
+- [`iis`](collector.iis.md)
+- [`logical_disk`](collector.logical_disk.md)
+- [`msmq`](collector.msmq.md)
+- [`mssql`](collector.mssql.md)
+- [`netframework_clrexceptions`](collector.netframework_clrexceptions.md)
+- [`netframework_clrinterop`](collector.netframework_clrinterop.md)
+- [`netframework_clrjit`](collector.netframework_clrjit.md)
+- [`netframework_clrloading`](collector.netframework_clrloading.md)
+- [`netframework_clrlocksandthreads`](collector.netframework_clrlocksandthreads.md)
+- [`netframework_clrmemory`](collector.netframework_clrmemory.md)
+- [`netframework_clrremoting`](collector.netframework_clrremoting.md)
+- [`netframework_clrsecurity`](collector.netframework_clrsecurity.md)
+- [`net`](collector.net.md)
+- [`os`](collector.os.md)
+- [`process`](collector.process.md)
+- [`service`](collector.service.md)
+- [`system`](collector.system.md)
+- [`tcp`](collector.tcp.md)
+- [`textfile`](collector.textfile.md)
+- [`vmware`](collector.vmware.md)