[Enhancement] Plugin to run on start - custom scripts

[Dexus]

Is your feature request related to a problem? Please describe.

When I need some special configs I need a way to Import them, before or after the initialisation is done.

Describe the solution you'd like

A way to run scripts at specific locations to install other packages or start services or perform tasks.

If one builds a container on this basis for certain areas of application, a plug-in system would be helpful, as with MariaDB and MySQL, for example, where an SQL file is imported or script is executed after initialisation.

It only requires a few points where one can hack so that certain tasks are completed before, for example, the database is fed with the GVMD data. Here as an example, create your own scanconfigs or a system user.