InnoDB storage engine
Components affected:
* `db_verify` now checks and corrects the table storage engine
* `db_verify` now checks and corrects the table default character set
* Note: Field character sets can still be overridden
* Note: When correcting, the entire table is converted to the target
charset.
* The alt_auth plugin now connects via PDO using the e107 default
charset, utf8mb4
* `e_db_pdo` now sets the charset to utf8mb4. This is currently not
customizable because it was previously not customizable.
* `install.php` now generates an `e107_config.php` file with
`$mySQLcharset = 'utf8mb4';`, though this option is not actually used.
* `install.php` now removes plugin tables before installing plugins.
* `e_db_mysql` now only accepts the `utf8mb4` charset. Previously, it
only accepted the `utf8` charset.
* `e_db_mysql` now configures `mysqli_real_escape_string` to match the
new default charset, `utf8mb4`.
* Plugin installations now use the preferred MySQL table storage engines
and charsets.
The preferred MySQL table storage engines are now mapped like so:
* If `ENGINE=MyISAM` is specified, the actual storage engine set will be
the first available of: InnoDB, Aria, Maria, MyISAM
* If `ENGINE=Aria` is specified, the actual storage engine set will be
the first available of: Aria, Maria, MyISAM
* If `ENGINE=InnoDB` is specified, the actual storage engine set will be
the first available of: InnoDB, XtraDB
* If `ENGINE=XtraDB` is specified, the actual storage engine set will be
the first available of: XtraDB, InnoDB
The preferred MySQL character set is now aliased like so:
* `utf8` => `utf8mb4`
* `utf8mb3` => `utf8mb3`
* `utf8mb4` => `utf8mb4`
Fixes: #4501
