[FIR] Improve diagnostic reporting & don't use error symbol for candidate if possible

Also introduce few new diagnostics:
- NONE_APPLICABLE more many inapplicable candidates
- HIDDEN for visible candidates

compiler/testData/diagnostics/tests/BinaryCallsOnNullableValues.fir.kt

@@ -6,9 +6,9 @@ class A() {
 fun f(): Unit {
     var x: Int? = 1
     x = null
-    x <!INAPPLICABLE_CANDIDATE!>+<!> 1
-    x <!INAPPLICABLE_CANDIDATE!>plus<!> 1
-    x <!INAPPLICABLE_CANDIDATE!><<!> 1
+    x <!NONE_APPLICABLE!>+<!> 1
+    x <!NONE_APPLICABLE!>plus<!> 1
+    x <!NONE_APPLICABLE!><<!> 1
     <!UNRESOLVED_REFERENCE!>x += 1<!>
 
     x == 1
@@ -22,7 +22,7 @@ fun f(): Unit {
     x === 1
     x !== 1
 
-    x<!INAPPLICABLE_CANDIDATE!>..<!>2
+    x<!NONE_APPLICABLE!>..<!>2
     x <!INAPPLICABLE_CANDIDATE!>in<!> 1..2
 
     val y : Boolean? = true