Fix broken URL path in generateUrl()

[austin-dudzik]

This pull request is to fix broken/missing issuer and user values that weren't getting added to the returned URL from the generateUrl() function.

After some digging, it appears that otpauth://totp is not read as a valid URL, as seen below. //totp is getting read as the pathname, instead of being included in the protocol, in which case seems to cause the URL() constructor to ignore attempts to set a new pathname on the URL.

To circumvent this, the pathname value, which includes the issuer and user values has been moved into the URL constructor, which now allows generateUrl() to return the proper, full otpauth:// URL value.

Before: otpauth://totp/?issuer=Issuer&period=30&secret=value

After: otpauth://totp/Issuer:[email protected]?issuer=Issuer&period=30&secret=value