[feat] sfpegActionBarCmp - Support Apex Form action

[pegros]

Is your feature request related to a problem? Please describe. Support ability to call an apex method from a form action in addition to LDS/DML.

Describe the solution you'd like The idea is to have the same feature as dmlForm but call a custom Apex method (implementing a virtual class) instead of doing a DML. This would enable to include callouts to external systems before executing a DML.

Describe alternatives you've considered N/A

Additional context Some legacy PEG components (callout form) was providing such a capability. May be mutualised with Issue #17