Add --admin-password to orbic-network installer, update docs

Also add some more debug-logging to telnet_send_file since it appears
to be janky on my device.

see #599

installer/src/orbic_auth.rs

@@ -0,0 +1,80 @@
+use anyhow::{Context, Result};
+use base64_light::base64_encode;
+use serde::{Deserialize, Serialize};
+
+/// Helper function to swap characters in a string
+fn swap_chars(s: &str, pos1: usize, pos2: usize) -> String {
+    let mut chars: Vec<char> = s.chars().collect();
+    if pos1 < chars.len() && pos2 < chars.len() {
+        chars.swap(pos1, pos2);
+    }
+    chars.into_iter().collect()
+}
+
+/// Apply character swapping based on secret (unchanged from original algorithm)
+fn apply_secret_swapping(mut text: String, secret_num: u32) -> String {
+    for i in 0..4 {
+        let byte = (secret_num >> (i * 8)) & 0xff;
+        let pos1 = (byte as usize) % text.len();
+        let pos2 = i % text.len();
+        text = swap_chars(&text, pos1, pos2);
+    }
+    text
+}
+
+/// Encode password using Orbic's custom algorithm
+///
+/// This function is a lot simpler than the original JavaScript because it always uses the same
+/// character set regardless of "password type", and any randomly generated values are hardcoded.
+pub fn encode_password(
+    password: &str,
+    secret: &str,
+    timestamp: &str,
+    timestamp_start: u64,
+) -> Result<String> {
+    let current_time = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap()
+        .as_secs();
+
+    // MD5 hash the password and use fixed prefix "a7" instead of random chars
+    let password_md5 = format!("{:x}", md5::compute(password));
+    let mut spliced_password = format!("a7{}", password_md5);
+
+    let secret_num = u32::from_str_radix(secret, 16).context("Failed to parse secret as hex")?;
+
+    spliced_password = apply_secret_swapping(spliced_password, secret_num);
+
+    let timestamp_hex =
+        u32::from_str_radix(timestamp, 16).context("Failed to parse timestamp as hex")?;
+    let time_delta = format!(
+        "{:x}",
+        timestamp_hex + (current_time - timestamp_start) as u32
+    );
+
+    // Use fixed hex "6137" instead of hex encoding of random values
+    let message = format!("6137x{}:{}", time_delta, spliced_password);
+
+    let result = base64_encode(&message);
+    let result = apply_secret_swapping(result, secret_num);
+
+    Ok(result)
+}
+
+#[derive(Debug, Serialize)]
+pub struct LoginRequest {
+    pub username: String,
+    pub password: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct LoginInfo {
+    pub retcode: u32,
+    #[serde(rename = "priKey")]
+    pub pri_key: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct LoginResponse {
+    pub retcode: u32,
+}