feat: generate jsonrpc headers at build time (#8350)

Discussion in https://github.com/chatmail/yerpc/issues/77. The necessary
yerpc changes for this PR are in
https://github.com/chatmail/yerpc/pull/78

This is also a preparation for #8330

deltachat-jsonrpc-bindings/build.rs

@@ -0,0 +1,6 @@
+use deltachat_jsonrpc::api::write_ts_bindings;
+use std::path::Path;
+
+fn main() {
+    write_ts_bindings(Path::new("typescript/generated"));
+}