load_script type checking - allow `np` datatypes in `cset` / `PVValue`

As a user on MERLIN I would like the following snippet to pass type checking:

```python
import numpy as np
from genie_python import genie as g

def runscript():
for psi in np.arange(30,130,10):
g.cset("Rot", psi, lowlimit=psi-0.1, highlimit=psi+0.1, runcontrol=True)
```

It currently fails with:

```
E: Argument of type "signedinteger[Any]" cannot be assigned to parameter "args" of type "PVValue"
```

`PVValue` should also include `np` types

### Acceptance criteria

- [ ] Above snippet passes type checking