Allow scientific notation in spinbox

#### Is your feature request related to a problem? Please describe

With very large or very small numbers, the values in the spinbox get harder to read:

#### Describe the solution you'd like

I believe, allowing input in scientific notation (E-notation, e.g. `1.2E-7`) and automatically converting large or small values to that will improve readability.

#### Describe alternatives you've considered

Custom textboxes, but they are not as handy as spinboxes for numbers.

#### Additional context

related: https://github.com/h2oai/wave/issues/1525

Start by locating the spinbox implementation and its existing input and display behavior; the issue does not name a file or test. Review related issue #1525, then define how scientific notation should be accepted and when large or small values should be reformatted before determining the necessary coverage.

Written by the indexing model from the issue text.