Tor service monitoring.

Add check-curl-tor command and service that uses it.
Add Tor service host objects.

.gitignore

@@ -87,3 +87,8 @@ Mkfile.old
 dkms.conf
 
 # End of https://www.gitignore.io/api/c
+
+# Vim backup files
+*.*~
+# Vim swap files
+*.*.swp

etc/README.md

@@ -0,0 +1,2 @@
+This tree contains all the configuration files for servers deployed by BlockchainCommons.
+**_WARNING:_ Do not commit any keys or secrets into this repository.**

etc/nagios4/apache2.conf

@@ -0,0 +1,49 @@
+# apache configuration for nagios 4.x
+
+ScriptAlias /cgi-bin/nagios4 /usr/lib/cgi-bin/nagios4
+ScriptAlias /nagios4/cgi-bin /usr/lib/cgi-bin/nagios4
+
+# Where the stylesheets (config files) reside
+Alias /nagios4/stylesheets /etc/nagios4/stylesheets
+
+# Where the HTML pages live
+Alias /nagios4 /usr/share/nagios4/htdocs
+
+<DirectoryMatch (/usr/share/nagios4/htdocs|/usr/lib/cgi-bin/nagios4|/etc/nagios4/stylesheets)>
+    Options FollowSymLinks
+    DirectoryIndex index.php index.html
+    AllowOverride AuthConfig
+    AuthDigestDomain "Nagios4"
+    AuthDigestProvider file
+    AuthUserFile	"/etc/nagios4/htdigest.users"
+    AuthGroupFile	"/etc/group"
+    AuthName	"Nagios4"
+    AuthType	Digest
+    # Require all	granted
+    Allow from      127.0.0.1 197.237.85.120
+    Require	valid-user
+    #
+    # The default Debian nagios4 install sets use_AUTHEntication=0 in
+    # /etc/nagios4/cgi.cfg, which turns off nagos's internal authentication.
+    # This is insecure.  As a compromise this default apache2 configuration
+    # only allows private IP addresses access.
+    #
+    # The <Files>...</Files> below shows how you can secure the nagios4
+    # web site so anybody can view it, but only authenticated users can issue
+    # commands (such as silence notifications).  To do that replace the
+    # "Require all granted" with "Require valid-user", and use htdigest
+    # program from the apache2-utils package to add users to
+    # /etc/nagios4/htdigest.users.
+    #
+    # A step up is to insist all users validate themselves by moving
+    # the stanza's in the <Files>..<Files> into the <DirectoryMatch>.
+    # Then by setting use_authentication=1 in /etc/nagios4/cgi.cfg youq
+    # can configure which people get to see a particular service from
+    # within the nagios configuration.
+    # 
+    # Require ip	::1/128 fc00::/7 fe80::/10 10.0.0.0/8 127.0.0.0/8 169.254.0.0/16 172.16.0.0/12 192.168.0.0/16
+</DirectoryMatch>
+
+<DirectoryMatch (/usr/share/nagios4/htdocs|/usr/lib/cgi-bin/nagios4)>
+    Options	+ExecCGI	
+</DirectoryMatch>