Fix(isEmail): Added support for internationalized domain names

[aabboudi]

Added the allow_idn option which is passed down to isFQDN to check if the domain name contains non-ASCII characters. It defaults to true to maintain original behavior. If set to false, it rejects domain names in non-Latin alphabets like Arabic, Chinese, Cyrillic, etc.

Closes #2390

References

For more information on IDNs, please refer to the following:

• RFC 5890 - Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework
• Internationalized Domain Names - ICANN

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (where applicable)
• Tests written (where applicable)
• References provided in PR (where applicable)

[rubiin]

Add tests too

[aabboudi]

Went ahead and added tests for isEmail and isURL with the new option, allow_idn, set to false.

[WikiRik]

Please update the README as well, see the checklist in the PR description

[Apidcloud]

Can we get this merged? AWS SES doesn't seem to support special characters in the domain, resulting in the error: "Domain contains control or whitespace". I believe this PR can also be combined with #2049 as it doesn't allow invisible characters as well (when combined with allow_utf8_local_part), but they should be added to the test cases.