If you're not intimately familiar with RFC 1808 it can be a bit tricky to
write tooz connection strings. In addition, some drivers do not document the
options that they recognize in a connection string. This can force a user to
read the driver code in order to figure out how to configure tooz to use said
driver, which should not be the case.
This change more explicitly documents the format of the connection string,
including which parts of an RFC 1808 URI it recognizes, and the options that
can be passed. It also clarifies which parts of the connection string are
optional (possibly because they have defaults) and which must always be
included.
Note that not every possible configuration is documented. For example, the
postgres driver supports multiple methods of configuring the connection host
and port. For consistency, I only documented the one that matches the other
drivers. This should be sufficient to allow a user to write a working
connection string.
This change also wires the etcd3 and etcd3gw drivers into the doc index since
they were missing before.
Change-Id: I66e54433115f27fb54badc2173f8f6044c49aacb
e76235b675