feat(outputs.graphite): Retry connecting to servers with failed send attempts

[sspaink]

resolve: #11429

The Graphite output plugin would only retry a server connection if it failed to send on all connections, this behavior wasn't obvious and if one server always remains up the other servers would never reconnect. This pull requests updates the retry logic to track the failed servers and reconnect to them after each send. I could also add a retry_delay configuration option similar to the inputs.cloud_pubsub and inputs.jti_openconfig_telemetry plugins, but from the issue the author mentioned this might not be necessary so I thought maybe we could add the config option if someone does require it?

I also updated the log.Errorf to log.Debugf for connection related errors, seeing as these servers will retry anyway this would help remove some noise in the logs which was also a concern in reported in #11429. If all servers fail it should print an error to the log though.

[powersj]

One small log change, thank you!

[telegraf-tiger]

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DEB	RPM	TAR GZ	ZIP
amd64.deb	aarch64.rpm	darwin_amd64.tar.gz	windows_amd64.zip
arm64.deb	armel.rpm	darwin_arm64.tar.gz	windows_i386.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz
armhf.deb	i386.rpm	freebsd_armv7.tar.gz
i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
mips.deb	riscv64.rpm	linux_amd64.tar.gz
mipsel.deb	s390x.rpm	linux_arm64.tar.gz
ppc64el.deb	x86_64.rpm	linux_armel.tar.gz
riscv64.deb		linux_armhf.tar.gz
s390x.deb		linux_i386.tar.gz
		linux_mips.tar.gz
		linux_mipsel.tar.gz
		linux_ppc64le.tar.gz
		linux_riscv64.tar.gz
		linux_s390x.tar.gz
		static_linux_amd64.tar.gz

[srebhan]

Looks good to me. Thanks @sspaink!