Well Event: Emit RPTRST/RPTSCHED as proper mnemonic lists

Schedule-level keywords whose OPM ParserRecord is a single ALL-sized item
(RPTRST, RPTSCHED, ...) are not positional — they take a free-form list
of mnemonic tokens like `BASIC=2 DEN ROCKC NORST=1`. Previously each
`keyword_data` entry became its own DeckItem, and OPM emitted them
either as truncated positional values or as a quoted, space-collapsed
single string.

Detect that schema shape in `RifEventKeywordFormatter::formatKeyword`
and pack the user's entries into one RawString DeckItem of mnemonic
tokens: `KEY` for FLAG items, `KEY=VALUE` otherwise.

To distinguish flag mnemonics (`DEN`) from `KEY=1`-style entries, add a
new `FLAG` value to `RimWellEventKeywordItem::ItemType` plumbed end to
end (Python -> GRPC -> Rimc -> storage -> formatter). The Python API
now maps `bool True` to FLAG and silently drops `bool False`.

For positional keywords (WCONHIST etc.) FLAG items have no value to
emit and are rendered as default markers ("1*").

A `rawStringItem` helper is added to `RifOpmDeckTools` so the
mnemonic-list path can produce DeckItems whose OPM output is not
quoted.

ApplicationLibCode/ProjectDataModel/WellEvents/RimKeywordEvent.cpp

@@ -98,6 +98,17 @@ void RimKeywordEvent::addDoubleItem( const QString& name, double value )
     m_items.push_back( item );
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RimKeywordEvent::addFlagItem( const QString& name )
+{
+    auto* item = new RimWellEventKeywordItem();
+    item->setItemName( name );
+    item->setFlag();
+    m_items.push_back( item );
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------