feat: define different network defaults for bins (#5307)

Description
---
This commit make a simple switch to define Network::default differently
for the different bins compiled for different networks.

Motivation and Context
---
Making us one step closer to smarter defaults, and one click, out of the
box.

How Has This Been Tested?
---
Manually

What process can a PR reviewer use to test or verify this change?
---
Compile the bin with `TARI_NETWORK=...` then validate the bin uses the
correct default

Fixes: #5310 

Breaking Changes
---

- [x] None
- [ ] Requires data directory on base node to be deleted
- [ ] Requires hard fork
- [ ] Other - Please specify

<!-- Does this include a breaking change? If so, include this line as a
footer -->
<!-- BREAKING CHANGE: Description what the user should do, e.g. delete a
database, resync the chain -->

Co-authored-by: SW van Heerden <swvheerden@gmail.com>

common/src/configuration/network.rs

@@ -74,10 +74,21 @@ impl Network {
 
 /// The default network for all applications
 impl Default for Network {
+    #[cfg(tari_network_mainnet)]
     fn default() -> Self {
         // TODO: set the default network to mainnet
         Network::StageNet
     }
+
+    #[cfg(tari_network_nextnet)]
+    fn default() -> Self {
+        Network::NextNet
+    }
+
+    #[cfg(all(not(tari_network_mainnet), not(tari_network_nextnet)))]
+    fn default() -> Self {
+        Network::Esmeralda
+    }
 }
 
 impl FromStr for Network {
@@ -195,7 +206,7 @@ mod test {
     #[test]
     fn network_default() {
         let network = Network::default();
-        assert_eq!(network, Network::StageNet);
+        assert_eq!(network, Network::Esmeralda);
     }
 
     #[test]