fix(history): Resolve the href in <base> correctly (#3819)

[ichaoX]

• Resolve the href in <base> correctly.

• In hash mode, the hash in base is automatically removed and the base trailing slash is distinguished.

• By default the result of router.resolve().href is the same as the actual switched URL.

Relates to: #3819, #2865

[netlify]

✅ Deploy Preview for vue-router-docs-v3 canceled.

Name	Link
🔨 Latest commit	992fd4b
🔍 Latest deploy log	https://app.netlify.com/sites/vue-router-docs-v3/deploys/646e0bb050065c00085989b1

[posva]

Thanks for the PR. Can you provide a failing test or boiled-down repro? Note a base should not contain a hash

[ichaoX]

An example of reproduction can be found in #3819, and you can view the source code of the Reproduction link.

Some browser extensions or proxies may modify <base>, and as a standard feature of html, it is necessary to support it correctly.

This PR should implement support for almost all legal baseURIs.
The <base> tag is then respected after ensuring the prerequisites of availability and consistency .
Support base.href containing relative URI or hash, even cross-origin cases.

[posva]

That base has a hash though. As I said, it cannot have a hash

[ichaoX]

That reproduction link contains several mistakes at the same time:

1. incorrect relative path
2. incorrect hash
3. there is an extra slash between base and hash

Additional reproduction links:

https://5s3iuf.csb.app/root/path.html

https://5s3iuf.csb.app/root/sameorigin.html

[ichaoX]

@posva
Do you need any other repro?