Add password strength meter and validation on the change password page

As raised by @megoth in https://github.com/solid/node-solid-server/pull/842

Not directly related, but more of a note to self: We've added repeat password on another page, we probably should do that here as well.

But for this case, we need to find a good markup of the password component. I've used two divs with col-md-3in the previous design, so might revert something a bit here, unless you have a better suggestion?

Originally posted by @megoth in https://github.com/solid/node-solid-server/pull/842

首先查看 pull request 842 中的讨论，并找到其中引用的 change-password 页面。在该页面中添加密码强度指示器和验证功能，包括讨论中建议的重复密码行为；完成的标准是页面能够直观地衡量密码强度，并拒绝无效或不匹配的密码。