Implement `AppClient` interface and related abstractions

[aorumbayev]

Description

The goal is to ensure complete feature parity between algokit-utils-ts and algokit-utils-py. AppClient interface and its public methods/properties/vars on utils-py must match the utils-ts implementation within the bounds of python best practices.

Technical Details

Acceptance Criteria

• AppClient interface on algokit-utils-py is implemented and has full feature parity with algokit-utils-ts

[aorumbayev]

Implemented as part of #119 and follow up beta patch PRs. Outcome itself is to be closed after prod release of utils-v3