Rejig the main save template to get rid of the separate system tiddler area

It dates from an ancient version of TW5, and is really redundant now.
It also meant that system tiddlers were not encrypted, which seems
confusing for end users.

core/templates/store.area.template.html.tid

@@ -1,13 +1,16 @@
 title: $:/core/templates/store.area.template.html
 
+\define saveFilter()
+[is[tiddler]] -[type[text/css]] -[type[application/javascript]has[module-type]] -[type[application/javascript]library[yes]] -[[$:/boot/boot.js]] -[[$:/boot/bootprefix.js]]
+\end
 <$reveal type="nomatch" state="$:/isEncrypted" text="yes">
 `<div id="storeArea" style="display:none;">`
-{{{ [!is[system]] ||$:/core/templates/html-div-tiddler}}}
+<$list filter=<<saveFilter>> template="$:/core/templates/html-div-tiddler"/>
 `</div>`
 </$reveal>
 <$reveal type="match" state="$:/isEncrypted" text="yes">
 `<!------------- Encrypted tiddlers --------->`
 `<pre id="encryptedStoreArea" type="text/plain" style="display:none;">`
-<$encrypt filter="[!is[system]]"/>
+<$encrypt filter=<<saveFilter>>/>
 `</pre>`
 </$reveal>

core/templates/tiddlywiki5.template.html.tid

@@ -30,10 +30,6 @@ title: $:/core/templates/tiddlywiki5.template.html
 {{$:/core/templates/static.content||$:/core/templates/html-tiddler}}
 </div>
 </noscript>
-<!----------- Miscellaneous system tiddlers ----------->
-<div id="systemArea" style="display:none;">
-{{{ [is[system]] -[type[text/css]] -[type[application/javascript]has[module-type]] -[type[application/javascript]library[yes]] -[[$:/boot/boot.js]] -[[$:/boot/bootprefix.js]] ||$:/core/templates/html-div-tiddler}}}
-</div>
 <!----------- Ordinary tiddlers ----------->
 {{$:/core/templates/store.area.template.html}}
 <!----------- Library modules ----------->