fix(inputs.cloudwatch): Option to produce dense metrics

[powersj]

Summary

Introduces a new config option called metric_format to the cloudwatch plugin to produce metrics in either sparse (default) or dense metric format. Sparse produces unique field names for every AWS Metric name + statistic (e.g. latency_avg, latency_sum, etc.), while dense will make the AWS metric name a tag (e.g. latency) and use fields for the various statisitics (e.g. avg, sum).

Checklist

• No AI generated code was used in this PR

[telegraf-tiger]

Download PR build artifacts for linux_amd64.tar.gz, darwin_arm64.tar.gz, and windows_amd64.zip.
Downloads for additional architectures and packages are available below.

⚠️ This pull request increases the Telegraf binary size by 1.10 % for linux amd64 (new size: 239.0 MB, nightly size 236.4 MB)

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Artifact URLs

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_arm64.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
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

[powersj]

@DStrand1, @srebhan please review, but do not merge till we get final feedback.

[srebhan]

Nice. Thanks @powersj! Will reassign to you, so merge whenever you feel it's ready...