Rename bootstrap leader (#7906)

* Rename bootstrap leader to bootstrap validator

It's a normal validator as soon as other validators enter the
leader schedule.

* cargo fmt

* Fix build

Thanks @CriesofCarrots!

sdk/src/genesis_config.rs

@@ -31,7 +31,7 @@ pub enum OperatingMode {
 
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct GenesisConfig {
-    /// when the network (bootstrap leader) was started relative to the UNIX Epoch
+    /// when the network (bootstrap validator) was started relative to the UNIX Epoch
     pub creation_time: UnixTimestamp,
     /// initial accounts
     pub accounts: BTreeMap<Pubkey, Account>,