WL#13068: Deprecate BINARY keyword for specifying _bin collations

In MySQL you can use the BINARY keyword to sepcifiy that you want the *_bin 
collation of a character set
(https://dev.mysql.com/doc/refman/8.0/en/binary-varbinary.html). This is not a
standard SQL feature, just syntactic sugar that adds to 
the confusion between the BINARY "character set" and *_bin collations.

Example:

mysql> create table foo (v varchar(10) binary);
Query OK, 0 rows affected (0.06 sec)

mysql> show create table foo;
+-------+-----....
| Table | Create Table                                                         
                                                                               
           
|
+-------+-----....
| foo   | CREATE TABLE `foo` (
  `v` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+-------+-----....
1 row in set (0.01 sec)

You can also write
    v varchar(10) character set utf8 binary       --> utf8_bin
    v varchar(10) character set latin1 binary     --> latin1_bin
etc.

I suggest this use of the BINARY keyword is deprecated.

F1: any use of the BINARY keyword in a query when (and only when) the goal is to
specify a _bin collation of a character set, should trigger a warning like this:

'BINARY as attribute of a type' is deprecated and will be removed in a future
release. Please use a CHARACTER SET clause with _bin collation instead

Examples:
# CREATE TABLE for column
create table t1 (v varchar(10) binary);
create table t1 (v varchar(10) character set latin1 binary);
create table t1 (v varchar(10) binary ascii);
create table t1 (v varchar(10) unicode binary);
alter table t1 modify v varchar(10) binary character set latin1;
select cast('a' as char(2) binary);
select convert('a', char(2) binary);

All above statements should send a warning.
But the ones below shouldn't, as they do select a
"binary" *charset*, not just a "_bin" collation of another charset

create table t1 (v binary(10));
create table t1 (v varchar(10)) character set binary;
alter table t1 character set binary;
create database mysqltest2 default character set = binary;
set names binary;
select convert("123" using binary);
select char(123 using binary);
create table t1 (v varchar(10) byte);

A few calls to push_warning() will be inserted in the right parser rules in
sql_yacc.yy