waveform: Add basic AnalogWaveform

[bkeryan]

• This contribution adheres to CONTRIBUTING.md.

What does this Pull Request accomplish?

Add the AnalogWaveform[_ScalarType_co] class, supporting the following operations:

• Construct a waveform with the specified sample count and/or capacity.
• Construct a wavefrom from a 1D array (np.ndarray, array.array) or sequence.
• Construct a list of waveforms from a 2D array (np.ndarray, Sequence[array.array]) or nested sequence.
• Access the waveform's raw and scaled data.
• Get and set extended properties.

AnalogWaveform[_ScalarType_co] is a generic class with the following type inference behavior:

• Constructing without a dtype returns an AnalogWaveform[np.float64].
• Constructing with a dtype literal returns an AnalogWaveform with that dtype, such as AnalogWaveform[np.int32].
• Constructing with a dtype string returns an AnalogWaveform[Any] because we can't infer the dtype in this case.
• AnalogWaveform.from_array_1d() and AnalogWaveform.from_array_2d() infer the data type from the input array, when possible.

Not implemented yet:

• Appending
• Scaling
• Getting and setting timing information

Why should this Pull Request be merged?

This is a significant chunk of the analog waveform functionality.

Implements AB#3082080

What testing has been done?

Wrote unit tests.

[github-actions]

Test Results

 10 files  ±  0   10 suites  ±0   10s ⏱️ +8s
 88 tests + 87   88 ✅ + 87  0 💤 ±0  0 ❌ ±0 
880 runs  +870  880 ✅ +870  0 💤 ±0  0 ❌ ±0 

Results for commit dff8c33. ± Comparison against base commit 77a431f.

♻️ This comment has been updated with latest results.