Remove deprecated methods from the examples and templates

[2ndshadow]

@abernatskiy 2024-07-09

All templates (the extended set) are up to date with the current SDK state. Fixing examples is done in parallel to their reorganization, which is a WIP.

est. 2d
Part of #414

DoD: All examples listed in subsquis-labs/substrate-examples (except RMRK) + a single non-trivial example