feat(content): routing to provided .blog paths

This is a starting point to dynamically loading `markdown` files as blog
entries. With this change the *doc/about.md* and *doc/blog.md* files
are no longer builded into the executable and instead read from the
filesystem during runtime (along with the new test file *doc/test.md*).

build.zig.zon

@@ -6,8 +6,8 @@
     .minimum_zig_version = "0.16.0-dev.463+f624191f9",
     .dependencies = .{
         .zterm = .{
-            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#7cd1fb139fbf45a3d99f8359dda0d198a283249a",
-            .hash = "zterm-0.3.0-1xmmEPf4GwA0W_Aj0yFGfg4efODoLB3y72LAprcAJwwe",
+            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#b3dc8096d76d6e246d48f9034a65997c0047c3c6",
+            .hash = "zterm-0.3.0-1xmmENP4GwBw65udohsoaxc9Kp4Yo7kORt4okY5pLslr",
         },
         .zlog = .{
             .url = "git+https://gitea.yves-biener.de/yves-biener/zlog#411a6dc358a3ef463ab704e2f6b887a019a5decf",