Remove deprecated/removed InnoDB variables - innodb_buffer_pool_instances

[mrlesmithjr]

Remove deprecated/removed InnoDB variables - innodb_buffer_pool_instances

[eRadical]

related: https://jira.mariadb.org/browse/MDEV-23397

[eRadical]

There are less deprecated variables than I initially thought.

Here is what I found:

• expire_logs_days - deprecated in MySQL, MariaDB added the new variable binlog_expire_logs_seconds - I would remove it altogether, if anyone needs that they can use via overrides option
• pid-file - remove it as this is not needed in SystemD servers (we can leave it for non-SystemD servers)
• innodb_buffer_pool_instances - deprecated as of MariaDB 10.5.1, removed from MariaDB 10.6 - there should be no problem in removing it even for old installs
• we can also talk about thread_stack which is set by default at 192K but starting from MariaDB 10.0 it is by default at least 288K. I think we should leave the default value as it is now large enough.

@mrlesmithjr Thoughts?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[eRadical]

not stale

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[eRadical]

Still here.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[eRadical]

not stale