fix issues related to encoding

[URenko]

Fix the way to disable encoding by introducing a new type Raw to solve #7456 and #6098.
See #7456 and the changes on the document for details.
The behavior of None was not changed to keep backward compatibility.

And fix vfs cache encoding described in #7760
The problem is when we create and write cache, we use the "OS" encoded ("OS" encoding is hardcoded for different operating systems, not specified by users).
But when we copy it to the remote (backend), we use local.Fs, which accept a name already encoded in "Standard" way.
So we need to send a "Standard" encoded name.

However, the "minimum setup" mentioned in #7760 has not been resolved. See my comment in it for details.
But it's an edge case.

Checklist

• I have read the contribution guidelines.
• I have added tests for all changes in this PR if appropriate.
• I have added documentation for the changes if appropriate.
• All commit messages are in house style.
• I'm done, this Pull Request is ready for review :-)

[ncw]

The behavior of None was not changed to keep backward compatibility.

I think I'd prefer None to do what people expect and not do any encoding. What was your reasoning here?

[URenko]

The behavior of None was not changed to keep backward compatibility.

I think I'd prefer None to do what people expect and not do any encoding. What was your reasoning here?

Backward compatibility.
Since encoding has been introduced for a long time. There must be many people already misused None.
If we change the behavior and they upgrade it without reading the changelog, we will break their storage. For example, they will need to resync tons of files (this is what happened to me when encoding was introduced. I don't what it to happen again to others : ).
And If they read the changelog, they will change to Raw and reorganize things.

[URenko]

@ncw any progress or further concern? :-)

[URenko]

fixed #7824

Specifically, it causes statements like rclone copy . to spontaneously miss if . expands to a path with a Full Width replacement character.