Subscription workflow redesign, libp2p/parachain state, other fixes

• replaced controller seed with user account auth (local auth without any servers);
• joined settings on one page;
• redesigned importing of settings (added drag&drop file uploading, one import one subscription), old imports still supported;
• redesigned creating new Polkadot accounts (now user can do it on demand for the controller and for the user as well);
• added "disconnect" button for the Polkadot extensions popover;
• added "libp2p/parachain" state;
• renamed navigation links;
• removed unnecessary pics for reducing package size.