Improve i18n/locale docs for the US clients

[sequba]

Description

• create Internationalization Overview guide that describes setting up the language and all the i18n-related configuration options (including decimalSeparator, functionArgSeparator) - add examples for the US locale
• add info to the Introduction page that we do support internationalization (with link to the Internationalization Overview)
• rename (or alias) default language from enGB to enUS (don't change the translations)
• use enUS date, currency & number formats in all the examples in the docs
• change Chineese example to US in date and time handling guide
• add a "notice" on top of the guide that the default date format is en-gb (number, currency?)
• fix error in date and time handling guide - mentioned wrong default format:
• make sure there is no more error in this guide

Links

• https://handsontable.github.io/hyperformula/guide/date-and-time-handling.html
• #912
• https://handsoncode.slack.com/archives/C031GBX62SE/p1659007424918559 (internal discussion)
• Related: #535

Type of issue

• [ ] Missing documentation
• [x] Error in the documentation
• [ ] Request for a demo
• [ ] Request for a tutorial, guide etc.
• [ ] Other issues, suggestions or ideas

[warpech]

change Chineese example to US in date and time handling guide

This example should include US am/pm time formatting. It is supported by HyperFormula (I can see it in the test suite) but not demonstrated in the docs.

[sequba]

Config params that should be covered by the Internationalization overview page:

• language
• functionArgSeparator, decimalSeparator, thousandSeparator
• accentSensitive, localeLang (in the context of string comparison)
• dateFormats, timeFormats, parseDateTime, stringifyDateTime, stringifyDuration (date/time format)
• currencySymbol

[sequba]

To achieve US locale compatibility:

• language: 'enUS' (add this language and make sure there are no differences in function names between 'enGB' and 'enUS')
• dateFormats: ['MM/DD/YYYY', 'MM/DD/YY']
• make sure timeFormats: ['hh:mm', 'hh:mm:ss.sss'] accepts AM/PM notation, add this information to the API reference
• decimalSeparator cannot be set to , because it must be different than functionArgSeparator (what about coercing strings to numbers?)
• localeLang: 'en-US' (make sure it works)

From: https://handsoncode.slack.com/archives/C031GBX62SE/p1658139775643749?thread_ts=1657905045.235899&cid=C031GBX62SE (internal discussion)

[sequba]

Closing as released in HyperFormula 2.2.0