MDEV-19917: Install Spider with a simple spider.cnf

To install Spider one can simply drop a /etc/mysql/conf.d/spider.cnf like

  [mariadb]
  plugin-load-add=ha_spider.so

This is automatically generated and installed when plugin is correctly
registered to plugin.cmake with its own component name. Many other plugins
such as Connect and RocksDB install in the same way.

This solved MDEV-19917 as the mere adding and removing of spider.cnf
automatically installs and uninstalls it.

Remove the overly complex and uncecessary install.sql from Spider,
if should not be needed in modern times anymore.

With this change there is no need for a uninstall.sql either.

Author: ottok

debian/mariadb-plugin-spider.install

@@ -1,2 +1,2 @@
+etc/mysql/conf.d/spider.cnf  etc/mysql/mariadb.conf.d
 usr/lib/mysql/plugin/ha_spider.so
-usr/share/mysql/install_spider.sql

debian/mariadb-plugin-spider.postinst

@@ -50,11 +50,8 @@ ELSEIF(PLUGIN_PARTITION MATCHES "^NO$")
 ELSE()
   INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/storage/spider/hs_client)
 
-  INSTALL(FILES
-    ${CMAKE_SOURCE_DIR}/storage/spider/scripts/install_spider.sql
-    DESTINATION ${INSTALL_MYSQLSHAREDIR} COMPONENT Server
-  )
-  MYSQL_ADD_PLUGIN(spider ${SPIDER_SOURCES} STORAGE_ENGINE MODULE_ONLY MODULE_OUTPUT_NAME "ha_spider")
+  MYSQL_ADD_PLUGIN(spider ${SPIDER_SOURCES}
+    STORAGE_ENGINE COMPONENT spider-engine MODULE_ONLY MODULE_OUTPUT_NAME "ha_spider")
   IF(NOT TARGET spider)
     RETURN()
   ENDIF()