docs: add Yandex Metrika plugin to community plugins

[sgromkov]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Hello everyone 👋

I created a plugin to connect Yandex Metrica to Docusaurus:
https://github.com/sgromkov/docusaurus-plugin-yandex-metrica

Yandex Metrica - it is a very popular in Russia web analytics tool. it's very similar to Google Analytics, and I was inspired by plugin-google-gtag while developing my own.

Typescript support will be in the next version of the plugin.

I am sure that many Russian Docusaurus users will find the plugin useful.

Test Plan

Test links

Deploy preview: https://deploy-preview-7340--docusaurus-2.netlify.app/community/resources

Related issues/PRs

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 63	🟢 100	🟢 100	🟢 100	🟢 90	Report
/docs/installation	🟠 87	🟢 99	🟢 100	🟢 100	🟢 90	Report

[Josh-Cena]

Thank you!