feat(clients): add nim-allographer client with BaraDB driver support

- Pure Nim wire protocol client (async + sync, no C FFI)
- Query Builder: fluent API, SQL generator, execution, transactions
- Schema Builder: create/alter/drop tables, column operations
- Connection pool with aging and timeout handling
- ORM integration via compile-time DB_BARADB switch
- Tests: test_open, test_query
- Documentation: README.md, PLAN_BARADB.md

clients/nim-allographer/documents/rdb/benchmark_result.md

@@ -0,0 +1,35 @@
+## index
+<!--ts-->
+   * [index](#index)
+   * [0.23.4](#0234)
+
+<!-- Created by https://github.com/ekalinin/github-markdown-toc -->
+<!-- Added by: root, at: Mon Jul 17 07:46:18 UTC 2023 -->
+
+<!--te-->
+
+## 0.23.4
+```sh
+cd example
+DB_POSTGRES=true nim c -r -d:release --threads:off -d:danger --mm:orc benchmark
+```
+
+query
+|num|time|
+|---|---|
+|1|0.938770656|
+|2|6.643012469|
+|3|6.493994112999999|
+|4|6.292020136999998|
+|5|6.618309597|
+|Avg|5.3972213944|
+
+update
+|num|time|
+|---|---|
+|1|0.3599897400000001|
+|2|0.2508196720000004|
+|3|0.1847369050000012|
+|4|0.2267158040000012|
+|5|0.2636497700000007|
+|Avg|0.2571823782000007|