Fix #262 distance oracle pool index

• Fixed #262 (closed): Switched to continuous indexing for naming distance evaluation files to prevent old files from being picked up by the inherent, avoiding unexpected behavior.
• Added crate-level documentation to provide an overview of the distance oracle's purpose and usage.
• Added a landing page for documentation duniter/index.html.
• Added a prefix check to prevent mismatches between the oracle and runtime versions, avoiding the Smith being penalized for a negligence error.
• Added log for distance-oracle started from the main binary.
• Refactored run and run_and_save oracle main functions:
  • Split into three thematic functions for better modularity:
    1. Checks if there is work to do and ensures files can be saved successfully.
    2. Handles the distance evaluation logic.
    3. Saves the computed distance to a file and cleans up outdated files.

distance-oracle/src/api.rs

@@ -19,11 +19,12 @@
 use crate::runtime;
 use log::debug;
 
-use subxt::utils::H256;
-
 pub type Client = subxt::OnlineClient<crate::RuntimeConfig>;
 pub type AccountId = subxt::utils::AccountId32;
 pub type IdtyIndex = u32;
+pub type EvaluationPool =
+    runtime::runtime_types::pallet_distance::types::EvaluationPool<AccountId, IdtyIndex>;
+pub type H256 = subxt::utils::H256;
 
 pub async fn client(rpc_url: impl AsRef<str>) -> Client {
     Client::from_insecure_url(rpc_url)
@@ -54,7 +55,7 @@ pub async fn current_pool(
     client: &Client,
     parent_hash: H256,
     current_pool_index: u32,
-) -> Option<runtime::runtime_types::pallet_distance::types::EvaluationPool<AccountId, IdtyIndex>> {
+) -> Option<EvaluationPool> {
     client
         .storage()
         .at(parent_hash)