Allow global override of default values for Profiles and ClusterProfiles

[filippolmt]

Is your feature request related to a problem? Please describe.
Currently, when implementing a Profile or a ClusterProfile, some parameters are set with hardcoded default values that cannot be overridden globally. For example:

• helm history is fixed at 2
• syncMode is set with a predefined default

This forces users to redefine these values inside the YAML of every single Profile or ClusterProfile, even when the same value should apply everywhere.

Describe the solution you'd like
Introduce the ability to configure global overrides for default values such as helm history and syncMode.
For instance, if I decide that all my Profiles and ClusterProfiles should have helm history=10, I should be able to configure this once globally, without having to repeat it in every YAML configuration file.

Describe alternatives you've considered
The only current alternative is to explicitly redefine the desired values in each YAML file, overriding the defaults on a per-resource basis. This approach is repetitive, increases the risk of inconsistencies, and adds unnecessary maintenance overhead.

Additional context
A practical example is the management of helm history: to increase it from the default 2, it must be explicitly set in every file. A global configuration would simplify management and ensure consistency across all profiles. The same applies to syncMode.