feat(core): Wait strategies foundation (#838)

Aligns testcontainers-python with the testcontainers community standard
wait strategy pattern used across Java, Go, and other implementations.
This provides a consistent developer experience and better
maintainability.

## Examples

From:

```
wait_for_logs(container, "Test Sample Image")
```

To:

```
from testcontainers.core.wait_strategies import LogMessageWaitStrategy

container.waiting_for(LogMessageWaitStrategy("Server started"))
```

## Backward Compatibility
No breaking changes - all existing code continues working
Deprecation warnings added to wait_for_logs() and
@wait_container_is_ready
Clear migration path provided in warning messages


### New:
core/testcontainers/core/wait_strategies.py - Strategy implementations
core/tests/test_wait_strategies*.py - Comprehensive test coverage
### Modified:
core/testcontainers/core/container.py - Added waiting_for() method
core/testcontainers/compose/compose.py - Added compose wait strategy
support
core/testcontainers/core/waiting_utils.py - Base classes and protocol

## Future Strategies to quickly follow
Foundation enables community-standard wait strategies:
HttpWaitStrategy, HealthcheckWaitStrategy, PortWaitStrategy,
CompositeWaitStrategy

## Testing
Unit tests with parameterized scenarios
Integration tests with real Docker containers
Protocol compliance verification
Backward compatibility validation