remove build.zig aws constant

This was always problematic, and bypasses the build system. It broke earlier
when moving to proper modules, and really, it is not worth using. The idea was
to allow usage of the SDK in a build context, but that does not work anyway,
because the build operates in a sandboxed environment that effectively bars
things like connecting to TLS endpoints. That is a feature of the build system,
not a bug, and issues like https://github.com/ziglang/zig/issues/14286
demonstrate that the zig team wants to sandbox even further. For downstream,
the right idea here is actually to create an executable that depends on aws
and run it as part of the build. This is where https://git.lerch.org/lobo/lambda-zig
is heading.

build.zig

@@ -3,8 +3,6 @@ const Builder = @import("std").Build;
 
 const models_subdir = "codegen/sdk-codegen/aws-models/"; // note will probably not work on windows
 
-pub const aws = @import("src/aws.zig");
-
 const test_targets = [_]std.Target.Query{
     .{}, // native
     .{ .cpu_arch = .x86_64, .os_tag = .linux },