Use merger module to fetch and sort tuples on router

Before this patch we used hand-crafted heap to sort tuples on
router. This patch removes it and changes to "merger" module
written in C.

"Merger" is available since Tarantool 2.2. Later "tuple-merger"
was introduced it's a version that is compatible with some
Tarantool 1.10 versions. In fact support several Tarantool
versions is quite complex task. Some msgpack helpers is not
avaliable in Tarantool 1.10 to solve this problem small
compatibility lawer is implemented.
Also "tuple-keydef" doesn't support collation_id options and it's
not so for built-in "key_def" module. We need to normalize index
parts and change "collation_id" to "collation" when create
"key_def" instance.

Closes #33

Co-authored-by: Elizaveta Dokshina <[email protected]>

Author: olegrok

.github/workflows/test_on_push.yaml

@@ -21,6 +21,7 @@ jobs:
         run: |
           curl -L https://tarantool.io/installer.sh | sudo VER=${{ matrix.tarantool-version }} bash
           sudo apt install -y tarantool-dev
+          tarantool --version
           ./deps.sh
 
       - name: Run linter
@@ -46,6 +47,7 @@ jobs:
           rm -f tarantool-enterprise-bundle-${{ matrix.bundle_version }}.tar.gz
           sudo cp tarantool-enterprise/tarantool /usr/bin/tarantool
           source tarantool-enterprise/env.sh
+          tarantool --version
           ./deps.sh
 
       - name: Run linter

CMakeLists.txt

@@ -28,3 +28,9 @@ install(
   DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/cartridge
   DESTINATION ${TARANTOOL_INSTALL_LUADIR}
 )
+
+# Don't include to rockspec as some Tarantool versions (e.g. 2.2 and 2.3)
+# don't have symbols required by "tuple-merger" and "tuple-keydef" modules.
+execute_process(
+    COMMAND bash "-c" "tarantoolctl rocks install tuple-merger 0.0.1"
+)