Add support for multiple SEC_UNLOCK sections in BD file

[IgorSukhov]

Summary
Enable the ability to unlock multiple features from different engines using the boot descriptor (BD) file with multiple SEC_UNLOCK sections

Background
Currently, there is no way to unlock features from different engines simultaneously using the BD file, as only the first SEC_UNLOCK section is processed.

Solution
To unlock several features from different engines, multiple SEC_UNLOCK sections can be used in the BD file:

'section (SEC_UNLOCK; 
    Unlock_Engine = "SNVS",
    Unlock_features = "ZMK WRITE")
{
}

section (SEC_UNLOCK; 
    Unlock_Engine = "OCOTP", 
    Unlock_features = "SRK REVOKE")
{
}

Tested with i.MXRT1061 processor.

[BohdanMarek]

Hi @IgorSukhov ,
Thank you for the proposal.
When implementing CSF commands processing we expected just one command of given type per BD file. This is a new requirement which is currently not supported.
Your solution solves the issue with multiple commands of same type. There is one downside and that is that the order of commands may not be kept. For example if user inserts one more command between two SEC_UNLOCK commands, the order of commands will be different to the BD file.

[BohdanMarek]

In order to parse multiple commands of a same type and keep the order of processed commands, we could perhaps update the API of SecCommandBase(and all its child classes) to something like this:
load_from_config(cls, command_config: CommandConfig, hab_config: HabConfig, search_paths: Optional[list[str]] = None) -> Self

Once this is updated in HabContainer class, we will be able to load multiple commands of the same type keeping the order taken from configuration file.