DI: Alternative approach to supply DI context to Components

[lhaze]

Up to now, binding a component with the Dependency Injection context is made by assuming that every Component has its __init__ fulfill the signature of (container: Container, **kwargs) -> None. This results in the following inconveniences:

• forces __init__'s argument structure which is one more thing to remember and may have an impact on inheriting a Component from extraneous classes
• doesn't supply the qualifier to Component that was created for; this might be a problem, e.g., in #60 (DAO doesn't have a ground to know structure being modeled)

[lhaze]

Fixed. Now, an instance constructed has its context under:

from pca.utils.dependency_injection import get_di_context

di_context: DIContext = get_di_context(instance)
qualifier = di_context.qualifier