Publish an alpha version of the Monero crate (#123)

* Label the version as an alpha

* Add versions to Cargo.tomls

* Update to Zeroize 1.5

* Drop patch versions from monero-serai Cargo.toml

* Add a repository field

* Move generators to OUT_DIR

IIRC, I didn't do this originally as it constantly re-generated them. 
Unfortunately, since cargo is complaining about .generators, we have to.

* Remove Timelock::fee_weight

Transaction::fee_weight's has a comment, "Assumes Timelock::None since 
this library won't let you create a TX with a timelock". Accordingly, 
this is dead code.

coins/monero/src/transaction.rs

@@ -119,10 +119,6 @@ impl Timelock {
     }
   }
 
-  pub(crate) fn fee_weight() -> usize {
-    8
-  }
-
   fn serialize<W: std::io::Write>(&self, w: &mut W) -> std::io::Result<()> {
     write_varint(
       &match self {