gtest genesis parsing

• only embed chainspec when feature enabled
• change existential deposit to match g1v1
• adapt genesis parsing to real-world data

# build with gtest feature
cargo build --release --features gtest --no-default-features
# run with custom genesis
DUNITER_GTEST_GENESIS=~/dev/py-g1-migrator/output/gtest_genesis.json duniter --tmp --alice --chain=gtest_dev

node/src/chain_spec/gtest_genesis.rs

@@ -89,12 +89,6 @@ struct Smith {
     certs_received: Vec<String>,
 }
 
-// Timestamp to block number
-// fn to_bn(genesis_timestamp: u64, timestamp: u64) -> u32 {
-//     let duration_in_secs = timestamp.saturating_sub(genesis_timestamp);
-//     (duration_in_secs / 6) as u32
-// }
-
 // copied from duniter primitives
 fn validate_idty_name(idty_name: &str) -> bool {
     idty_name.len() >= 3
@@ -117,21 +111,6 @@ pub fn build_genesis(
 ) -> Result<GenesisConfig, String> {
     // preparatory steps
 
-    // define genesis timestamp
-    let genesis_timestamp: u64 =
-        if let Ok(genesis_timestamp) = std::env::var("DUNITER_GENESIS_TIMESTAMP") {
-            genesis_timestamp
-                .parse()
-                .map_err(|_| "DUNITER_GENESIS_TIMESTAMP must be a number".to_owned())?
-        } else {
-            use std::time::SystemTime;
-            SystemTime::now()
-                .duration_since(SystemTime::UNIX_EPOCH)
-                .expect("SystemTime before UNIX EPOCH!")
-                .as_secs()
-        };
-    log::info!("genesis timestamp: {}", genesis_timestamp);
-
     // declare variables for building genesis
     // -------------------------------------
     // track if fatal error occured, but let processing continue