[IMP] app, compiler: introduce t-out

t-out automatically escaped content when it is a string not marked
with the `markup` function

t-out renders the raw content if it is a Block, or if it has been marked
with the `markup` funtion.

t-esc has been kept since it is safe and is optimized to render text nodes.

all t-raw calls are in fact the same as t-out.

tests/components/props.test.ts

@@ -82,12 +82,12 @@ describe("basics", () => {
     expect(fixture.innerHTML).toBe("<div><span>42</span></div>");
   });
 
-  test("t-set with a body expression can be passed in props, and then t-raw", async () => {
+  test("t-set with a body expression can be passed in props, and then t-out", async () => {
     class Child extends Component {
       static template = xml`
         <span>
           <t t-esc="props.val"/>
-          <t t-raw="props.val"/>
+          <t t-out="props.val"/>
         </span>`;
     }
     class Parent extends Component {