improved support for SRS signal generators

[qku]

Description

This PR introduces improvements to the microwave hardware file for Stanford Research Systems (SRS) signal generators.

• support for all current SRS signal generators (see manufacturer website)
• proper matching of the model identifier to supported functions and hardware constraints
• check for error after every write command
• display current frequency during scan
• type annotations and documentation

Motivation and Context

We are using a non-vector SRS signal generator in our lab. It was not compatible with the current hardware file due to the usage of commands which are defined exclusively for vector models.

How Has This Been Tested?

Tested on real hardware (SG384) with the ODMR toolchain.

Types of changes

• [ ] Bug fix
• [X] New feature
• [ ] Breaking change (Causes existing functionality to not work as expected)

Checklist:

• [X] My code follows the code style of this project.
• [X] I have documented my changes in /docs/changelog.md.
• [ ] My change requires additional/updated documentation.
• [X] I have updated the documentation accordingly.
• [ ] I have added/updated the config example for any module docstrings as necessary.
• [X] I have checked that the change does not contain obvious errors (syntax, indentation, mutable default values, etc.).
• [ ] I have tested my changes using 'Load all modules' on the default dummy configuration.
• [ ] All changed Jupyter notebooks have been stripped of their output cells.

[qku]

Thank you for reviewing @NicolasStaudenmaier ! I changed the visa imports as suggested.