feat: set catalog as thread safe

wip: add a thread safe way to access items; change upsert

wip: change catalog.delete to be thread safe

wip: change catalog.load_by_* to be thread safe

wip: add a thread safe way to access items in readonly mode; change
catalog.get

wip: change catalog.persist to be thread safe

wip: disable examples temprarily

wip: remove catalog_new.rs file

wip: ignore result of iteration

wip: disable lib example

wip: enable catalog.delete tests

wip: enable catalog.get tests

wip enalbe catalog.init tests

wip: enable catalog.insert_many tests

wip: enable catalog.load_by_class tests

wip: enable catalog.load_by_id tests

wip: add len() and is_empty() convenience thread safe method to catalog

wip: use convenience methods for len and is_empty checks

wip: enable catalog.load_by_id and catalog.new tests

wip: enable catalog.upsert tests

wip: enable catalog.persist test; add catalog.contains_key

wip: enable catalog.load_by_filter tests

wip: enable sqlite_* tests

wip: enable list_by_class with tests

wip: enable list_by_class_and_subclass with tests

wip: enable integration tests

wip: switch iter to into_iter for tests

01.workspace/heave/src/imp/catalog_len.rs

@@ -0,0 +1,7 @@
+use crate::*;
+
+impl Catalog {
+    pub fn len(&self) -> Result<usize, FailedTo> {
+        self.with_items(|items| Ok(items.len()))
+    }
+}