Updated envoy website URLs to new domain

[RichardoC]

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[istio-testing]

Hi @RichardoC. Thanks for your PR.

I'm waiting for a istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[RichardoC]

I've deliberately excluded everything under archive because this (may) have been a valid URL when those pages were created

[kfaseela]

cc @phlax

[kfaseela]

/ok-to-test

[craigbox]

I've changed to the glossary definition throughout, as the context of all of them is a link to the project, not to the docs.

When the preview is ready I'll confirm that the {{<gloss>}} shortcode does the right thing for the ZH pages too.

[craigbox]

Suggested change

	Istio 的代理基于 [`Envoy`](https://www.envoyproxy.io/docs/envoy/)，它作为数据平面的用户空间守护进程实现的，使用标准套接字与网络层交互。这使它在处理方面具有很大的灵活性，并允许它在容器中分发（和升级！）。
	Istio 的代理基于 {{<gloss envoy>}}Envoy{{</gloss>}}，它作为数据平面的用户空间守护进程实现的，使用标准套接字与网络层交互。这使它在处理方面具有很大的灵活性，并允许它在容器中分发（和升级！）。

[craigbox]

(p.s. if this PR were updated to "maintainers can edit" then I am happy to make these changes myself.)

[RichardoC]

(p.s. if this PR were updated to "maintainers can edit" then I am happy to make these changes myself.)

Have updated, sorry about that

[wilsonwu]

/test lint