* EditUrl function
* normalize blog/docs regarding the editUrl feature + editUrl function
* editUrl fn => always inject posix style relative paths, make tests more reliable
(see also https://github.com/facebook/docusaurus/issues/4124)
* fix editUrl on windows
* add new docs versioning options
* Add some tests for new versioning options
* Add some docs for version configurations
* try to fix broken link detection after /docs/ root paths have been removed on deploy previews
* improve dev/deploypreview versioning configurations
* disable custom current version path, as it produces broken links
* readVersionDocs should not be order sensitive
* fix versions page according to versioning config
* fix versions page according to versioning config