Add Option to Configure Number of Templates Generated in Templatic Augmentation

**Current State**
```python
...

TemplaticAugment(
    templates=templates,
    task=TaskManager("ner"),
    generate_templates=True,
    show_templates=True
)
```
**Suggested Solution**
```python
...

TemplaticAugment(
    templates=templates,
    task=TaskManager("ner"),
    generate_templates=True,
    show_templates=True
    additional_templates_count=10 # 
)
```

