Create `jetzig.http.Response` when `std.http.Server.Response` is created
and delegate all management of `std.http.Server.Response` to
`jetzig.http.Response`. Using this internally means we use the same
internal interface for the `Response` as the user, which gives us things
like response headers management in views for free (user simply calls
`request.response.headers.append()` etc.).
Implement `jetzig.http.Request.params()` which parses either a JSON
request body or a query param string into a `jetzig.data.Value`.
Allow configuring params for static site generation - configure an array
of params for each endpoint which is then parsed at build time and a
separate JSON and HTML output is generated for each by invoking the
relevant view function and passing in resource ID/params. Params are
stored in generated `routes.zig` for route matching at run time.
Remove `anyerror` from example definitions - we only need this in the
struct definition, no need to have explicit error set defined in
user-defined view functions.
Generate views defined with `request: *jetzig.http.StaticRequest` as
static content into `static/` directory so that exported JSON and HTML
can be rendered direct from disk, skipping runtime rendering.
