When reporting missing functions from Plugins, ensure messages do not occur too often

[netniV]

Describe the bug

Warnings about missing functions should be debounced. Also, the debounce function should used the passed Frequency (named incorrectly)

[netniV]

Message has now been adjusted and the debounce function now accepts the passed parameter.

[netniV]

Example of truncated key:

2023-06-08 23:25:18 - CMDPHP ERROR: debounce key was truncated from debounce_mpf_intropage_include/settings.php_intropage_config_form to debounce_mpf_intropage_include/settings.php_introp Backtrace: (/clog.php[27]:include(), /include/auth.php[27]:require_once(), /include/global.php[548]:include_once(), /include/global_form.php[2362]:api_plugin_hook(), /lib/plugins.php[90]:debounce_run_notification(), /lib/functions.php[7297]:cacti_debug_backtrace())

2023-06-08 23:25:09 - PLUGIN WARNING: Function "intropage_config_form" does not exist in intropage/include/settings.php for hook "config_form"

NOTE: This was corrected before patch was submitted