WL#9495: Update schema tables of dynamic plugins into data dictionary.

Affects: Server-8.0   —   Status: Complete

The main aim of this WL is to,

* This WL focuses to present INFORMATION_SCHEMA (I_S) tables
  metadata to be visible through I_S.TABLES. Following are the
  three areas where we can find I_S tables in MySQL server.

   1. Server I_S table.
   2. Builtin plugin's I_S table.
   3. Dynamic plugin's I_S table.

  We need to write metadata of above I_S tables to data
  dictionary (DD) tables, so that the system view I_S.TABLES
  picks it.

* Update DD tables when a plugin is loaded or unloaded.
  This can happen when server is started by command line
  options or by INSTALL/UNINSTALL commands.

* Server should update DD tables with I_S table
  metadata based when I_S table structure is changed, using
  a version number.

* Move creation of system views from mysql_system_tables.sql
  script to server initial start similar to the way the
  DD tables are created.

* Upgrade system views by introducing I_S version number,
  similar to the way we have DD version.

* Hide I_S.*_DYNAMIC and I_S.SHOW_* internal system view
  from user.