Allow extra attrs provided to <Select> to be passed through to the DOM element

[davwheat]

Changes proposed in this pull request:

• Extra attrspassed to the Select component are given straight to the DOM element
  • This is critical for accessibility. Currently, there is no way to provide a11y attrs (such as for, id, aria-described-by, etc.) to the DOM element.
• Custom class names can be provided to the outer wrapping element for easier customisability
• Custom attrs can also be passed to the wrapper via the wrapperAttrs attr

Reviewers should focus on:

Should we allow a way to pass any attrs wanted to the outer element, too? Something like a wrapperAttrs attribute? Done!

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).

[dsevillamartin]

Should we allow a way to pass any attrs wanted to the outer element, too? Something like a wrapperAttrs attribute?

This sounds like a good idea.

[davwheat]

This sounds like a good idea.

@datitisev Implemented!

[davwheat]

I'll fix formatting in a second.