feat(schedule)!: move schedule parser, downloader, and updater to external library

This can be used to support more schedule formats in the future.

providers/base/src/hasher.rs

@@ -0,0 +1,53 @@
+use sha1::Digest;
+use sha1::digest::OutputSizeUser;
+use sha1::digest::typenum::Unsigned;
+use std::hash::Hasher;
+
+/// Hesher returning hash from the algorithm implementing Digest
+pub struct DigestHasher<D: Digest> {
+    digest: D,
+}
+
+impl<D> DigestHasher<D>
+where
+    D: Digest,
+{
+    /// Obtain hash.
+    pub fn finalize(self) -> String {
+        static ALPHABET: [char; 16] = [
+            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F',
+        ];
+        
+        let mut hex = String::with_capacity(<D as OutputSizeUser>::OutputSize::USIZE * 2);
+
+        for byte in self.digest.finalize().0.into_iter() {
+            let byte: u8 = byte;
+
+            hex.push(ALPHABET[(byte >> 4) as usize]);
+            hex.push(ALPHABET[(byte & 0xF) as usize]);
+        }
+
+        hex
+    }
+}
+
+impl<D> From<D> for DigestHasher<D>
+where
+    D: Digest,
+{
+    /// Creating a hash from an algorithm implementing Digest.
+    fn from(digest: D) -> Self {
+        DigestHasher { digest }
+    }
+}
+
+impl<D: Digest> Hasher for DigestHasher<D> {
+    /// Stopper to prevent calling the standard Hasher result.
+    fn finish(&self) -> u64 {
+        unimplemented!("Do not call finish()");
+    }
+
+    fn write(&mut self, bytes: &[u8]) {
+        self.digest.update(bytes);
+    }
+}