Add otpauth uri

[comuttun]

Implemented otpauth URI parse method

[kwart]

Hi comutt,
thank you for the contribution. I think it's a nice feature.
Nevertheless I see some problems in the current implementation:

• if the users choose the otpauth: based profile, and they want to review the options, then the URI field is empty (end there is even no back button)
• users see the key-generator in the menu even if they use an otpauth: based profile
• after application restart and going to an otpauth: based profile and choose Options from the menu, users will see empty options page
• if users has profiles with both otpauth: and manual mode, and they switch between them, then the Options form behaves strange (sometime it's empty, sometime there are options from manualmode used for otpauth profile...)

Have a look at he mentioned problems and update the PR once fixed, please.