Add basic Excel export

moneymgr_backend/Cargo.lock

@@ -2282,6 +2282,7 @@ dependencies = [
  "rand 0.9.0",
  "rust-embed",
  "rust-s3",
+ "rust_xlsxwriter",
  "serde",
  "serde_json",
  "sha2",
@@ -2990,6 +2991,15 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "rust_xlsxwriter"
+version = "0.86.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34ab327483e6b6fc521b7e303691c14bf3624a68e0cb4c2b9f9c5d692e07f637"
+dependencies = [
+ "zip",
+]
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.24"