feat(outputs.bigquery): Project is no longer a required field

[Hipska]

Required for all PRs

• Updated associated README.md.
• Wrote appropriate unit tests.
• Pull request title or commits are in conventional commit format

This is a preparation for a bigger rewrite of the BigQuery plugin.

The provided credentials file has the project name as well, so the library will try to auto-detect it from the file. There is also no backwards compatibility breakage, as the parameter was a required field before.

[srebhan]

Thanks for the PR @Hipska! Two small questions...

[srebhan]

@Hipska there is also a dependency license-entry missing...

[Hipska]

My local checker asked for another dependency to be added, but CircleCI didn't, so I removed it again.

[srebhan]

Thanks for your effort @Hipska!

[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_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]

Thanks