Add custom keywords, and Chinese translation

[youthlin]

test

• npm run test passed.

what changed and why

• README.md: add a link to README_zh.md
• dev/App.vue: add a property name lang, so I can use <Demo lang='zh_CN'/> in docs/zh/demo.md
• dev/components/DemoAlert.vue: a demo for custom global properties
• dev/components/DemoDateFormat.vue: add zh locale
• dev/i18n.ts: new file, used by dev/main.ts and docs/.vuepress/client.ts
• docs/.vuepress/config.ts: enable Internationalization
• docs/configuration.md: update default config, add globalProperties
• docs/extraction.md: update default config, add jsExtractorOpts
• docs/zh/*: add zh translation
• gettext.config.js: update extract config, add locale, add jsExtractorOpts to extract the custom keywords
• scripts/config.ts: add jsExtractorOpts to GettextConfig
• scripts/extract.ts: add extracors to support custom keywords
• scripts/gettext_extract.ts: add comment for msginit
• scripts/utils.ts: pass env to child process, so msginit can access the GETTEXTCLDRDIR variable
• src/index.ts: add support for custom global properties
• src/typeDefs.ts: update type defs of GetTextOptions, GettextConfig

[youthlin]

fix https://github.com/jshmrtn/vue3-gettext/issues/20

[lzurbriggen]

Hi @youthlin, thanks for your PR! I will need some time to review this, you may need some patience.

I have to admit I'm a bit ~weary~ wary about adding Chinese docs, mainly because I have no way to maintain them myself. I will probably merge them, but please add a warning disclaimer to make it clear that the chinese docs are not actively maintained/that they may diverge from the package version.

[youthlin]

Hi @youthlin, thanks for your PR! I will need some time to review this, you may need some patience.

I have to admit I'm a bit weary about adding Chinese docs, mainly because I have no way to maintain them myself. I will probably merge them, but please add a warning disclaimer to make it clear that the chinese docs are not actively maintained/that they may diverge from the package version.

Thanks for your reply! I have added a translation notes on docs, please help review. I would watch this repo, and can synchronize the Chinese translation regularly.

[youthlin]

@lzurbriggen Hi, can those code to be merged? What should I do more to help

[jeremyzahner]

@lzurbriggen Hi, can those code to be merged? What should I do more to help

Hi @youthlin!

@lzurbriggen is back in tomorrow. I guess he will get back to you as soon as he can.

[lzurbriggen]

@youthlin I don't really have the time to review this in detail, but it looks good in general. I'll merge this and create a pre-release. I may make some changes before I create a final release.