Add solana-install-init binary (#4613)

* Add solana-install-init binary

* Add Enter prompt on solana-install-init exit for Windows users

install/src/main-install-init.rs

@@ -0,0 +1,27 @@
+use std::process::exit;
+
+#[cfg(windows)]
+fn press_enter() {
+    // On windows, where installation happens in a console that may have opened just for this
+    // purpose, give the user an opportunity to see the error before the window closes.
+    println!();
+    println!("Press the Enter key to continue.");
+
+    use std::io::BufRead;
+    let stdin = std::io::stdin();
+    let stdin = stdin.lock();
+    let mut lines = stdin.lines();
+    lines.next();
+}
+
+#[cfg(not(windows))]
+fn press_enter() {}
+
+fn main() {
+    solana_install::main_init().unwrap_or_else(|err| {
+        println!("Error: {}", err);
+        press_enter();
+        exit(1);
+    });
+    press_enter();
+}