Add check for URL consistency between URL mentioned in "This version" and its location.

[jennyliang220]

If document URL starts with 'https://www.w3.org/TR/xxxx/', check it's consistant with URL of 'This version'

[jennyliang220]

Use case: reinstall of the document. And make sure it doesn't break echidna

[jennyliang220]

Use case 2: the document is installed at https://www.w3.org/TR/2021/WD-i18n-localizable-manifests-20210819/, but this version link is https://www.w3.org/TR/2021/WD-localizable-manifests-20210819/, a 404. Thank you linkchecker for giving an error.