Replace vaxis with zterm (#1)

Vaxis sadly cannot be used for applications which want to serve their contents via ssh to the (remote) user.

Instead I wrote my own tui library [zterm](https://gitea.yves-biener.de/yves-biener/zterm), which this tui application now uses. This will serve two purposes:
1. implement the tui application and be servable through ssh (see [wish-serve](https://gitea.yves-biener.de/yves-biener/wish-serve))
2. serve as documentation and showcase of an example application for **zterm**

Reviewed-on: #1

build.zig

@@ -16,16 +16,12 @@ pub fn build(b: *std.Build) void {
     const optimize = b.standardOptimizeOption(.{});
 
     // Dependencies
-    const vaxis_dep = b.dependency("vaxis", .{
-        .optimize = optimize,
-        .target = target,
-    });
-    const zlog_dep = b.dependency("zlog", .{
+    const zlog = b.dependency("zlog", .{
         .optimize = optimize,
         .target = target,
         .timestamp = true,
     });
-    const zmd_dep = b.dependency("zmd", .{
+    const zterm = b.dependency("zterm", .{
         .optimize = optimize,
         .target = target,
     });
@@ -36,9 +32,8 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
-    exe.root_module.addImport("vaxis", vaxis_dep.module("vaxis"));
-    exe.root_module.addImport("zlog", zlog_dep.module("zlog"));
-    exe.root_module.addImport("zmd", zmd_dep.module("zmd"));
+    exe.root_module.addImport("zlog", zlog.module("zlog"));
+    exe.root_module.addImport("zterm", zterm.module("zterm"));
 
     // This declares intent for the executable to be installed into the
     // standard location when the user invokes the "install" step (the default