Create new configuration models

[RakhithaRR]

A new configuration model will be introduced for the domain service since the previous carbon dependencies will no longer be used with new services.

Proposed Approach

• Single toml file to contain all the configurations. According to the call with the ballerina team, we can use the Config.toml for this purpose.
• Record mappings on the ballerina side (similar to api-manager.xml).
• Startup service to start all internal components related to apimgt (similar to APIMStartupComponent). Need to use ballerina interops for this too to call as a function from the ballerina code.
• Use an object mapper from the Java side to map the configurations in runtime.