Fix some issues related to #65

This commit prevents the basic bug of allowing a user to click "Next" without
entering any information. This is done by telling QT which fields are mandatory.

I am not sure if it fixes the "Cancel button does a coredump" because I cannot
reproduce that.

I also made various strings use the translation file.

I removed the "Back" button from the first page, because that makes no sense.

I removed the "Passphrase don't match" red text that is shown by default, because
it was ugly and immediately shows users a negative "you did something wrong" as their
very first visual of the wallet. That seemed like bad UI/UX. Now we only show red
text there if passwords are too short or do not match.

I made the TOS button text red, which makes it more clear that it's necessary
to click it.

As a consequence of these changes, you cannot input ANY values until the TOS radio
button is clicked, so it seemed important to highlight it in red. Otherwise users
may click other areas and it seems like nothing works.

I deleted an unused file restoreSeed.ui .

src/firsttimewizard.h

@@ -1,4 +1,4 @@
-// Copyright 2019-2020 The Hush developers
+// Copyright 2019-2022 The Hush developers
 // Released under the GPLv3
 #ifndef FIRSTTIMEWIZARD_H
 #define FIRSTTIMEWIZARD_H
@@ -31,8 +31,10 @@ public slots:
 
 protected:
     int nextId() const;
+    virtual void initializePage();
 
 private:
+    FirstTimeWizard* parent;
     enum {
         Page_NewOrRestore,
         Page_New,
@@ -49,10 +51,17 @@ private:
 };
 
 class NewOrRestorePage: public QWizardPage {
+
 public:
  
     NewOrRestorePage(FirstTimeWizard* parent);
 
+protected:
+    virtual void initializePage();
+
+private:
+    FirstTimeWizard* parent;
+
 };
 
 
@@ -83,6 +92,4 @@ private:
     Ui_RestoreSeedForm form;
 };
 
-
-
 #endif // FIRSTTIMEWIZARD_H