🔧 Optional filter by application name in application-roles-per-entity-type endpoint

[edgarvonk]

As a client of the PABC application-roles-per-entity-type endpoint
I want to optionally specify an application name in my request
so that I only receive the relevant application roles and entity types for that specific application, instead of getting results for all applications.

ACCEPTANCE CRITERIA

• The endpoint accepts an optional applicationName (or similar) parameter
• When applicationName is provided, only entity types and application roles for that application are returned
• When no applicationName is provided, the current behavior (returning all roles) remains unchanged
• You can still use the same JSON to populate the database (see 🔄(Re-)create a complete data set during deployment #17)

DETAILS

• In this story we will also change the way we store Applications: applications and their names will be stored centrally in a separate table in the PABC database
• Other tables will refer to this new table via a foreign key, instead of storing application names as plain strings in multiple places
• A migration with dataloss is acceptable
• More context and background can be found here: ZAC - PABC alignment meeting, 2025-07-21