feat(all): Task store

implements:
https://github.com/meilisearch/specifications/blob/develop/text/0060-refashion-updates-apis.md

linked PR:

- #1889
- #1891
- #1892
- #1902
- #1906
- #1911
- #1914
- #1915
- #1916
- #1918
- #1924
- #1925
- #1926
- #1930
- #1936
- #1937
- #1942
- #1944
- #1945
- #1946
- #1947
- #1950
- #1951
- #1957
- #1959
- #1960
- #1961
- #1962
- #1964

- https://github.com/meilisearch/milli/pull/414
- https://github.com/meilisearch/milli/pull/409
- https://github.com/meilisearch/milli/pull/406
- https://github.com/meilisearch/milli/pull/418

- close #1687
- close #1786
- close #1940
- close #1948
- close #1949
- close #1932
- close #1956

meilisearch-lib/src/index_controller/dump_actor/loaders/v4.rs

@@ -0,0 +1,45 @@
+use std::path::Path;
+
+use heed::EnvOpenOptions;
+use log::info;
+
+use crate::analytics;
+use crate::index_controller::dump_actor::Metadata;
+use crate::index_resolver::IndexResolver;
+use crate::options::IndexerOpts;
+use crate::tasks::TaskStore;
+use crate::update_file_store::UpdateFileStore;
+
+pub fn load_dump(
+    meta: Metadata,
+    src: impl AsRef<Path>,
+    dst: impl AsRef<Path>,
+    index_db_size: usize,
+    meta_env_size: usize,
+    indexing_options: &IndexerOpts,
+) -> anyhow::Result<()> {
+    info!(
+        "Loading dump from {}, dump database version: {}, dump version: V4",
+        meta.dump_date, meta.db_version
+    );
+
+    let mut options = EnvOpenOptions::new();
+    options.map_size(meta_env_size);
+    options.max_dbs(100);
+    let env = options.open(&dst)?;
+
+    IndexResolver::load_dump(
+        src.as_ref(),
+        &dst,
+        index_db_size,
+        env.clone(),
+        indexing_options,
+    )?;
+    UpdateFileStore::load_dump(src.as_ref(), &dst)?;
+    TaskStore::load_dump(&src, env)?;
+    analytics::copy_user_id(src.as_ref(), dst.as_ref());
+
+    info!("Loading indexes.");
+
+    Ok(())
+}