Remove Bootstrap 3 button loading state method

[JulieWinchester]

Hi! While upgrading our Hyrax-based app to Hyrax 5, we noticed that Browse Everything's submit button was broken for our app. I'll attach a screenshot below of the specific error we're seeing. Running it down, it seems like the root cause is this one line using Bootstrap 3 plugin behavior that's been removed in Bootstrap 4 (https://getbootstrap.com/docs/3.4/javascript/#buttons-stateful). In our specific case, this line ends up trying to call jQuery UI's button widget (https://api.jqueryui.com/button/), which produces the error in the screenshot.

This PR removes the outdated button loading state call from Bootstrap 3. The startWait() call immediately below should ensure the submit button gets disabled after being clicked regardless.

Thanks for considering the PR.

Screenshot of error:

[jrochkind]

The README still says b-e is supposed to work with bootstrap 3 and 4 -- but maybe nobody is actually doing that and I don't know if it really does?

Should we adjust README to no longer say 3, if we're doing this?

[jrochkind]

Also, I'm eager to see someone else who is actually using this gem (not a fork!), I've been having trouble finding any!

Since I have you, can you let us know what adapters you use?

[JulieWinchester]

Also, I'm eager to see someone else who is actually using this gem (not a fork!), I've been having trouble finding any!

Since I have you, can you let us know what adapters you use?

Of course! We've been using vanilla BrowseEverything for years with MorphoSource. Most of our uploads come from users via the usual Hyrax file post method, but since we're a repository where users sometimes upload files of very large file sizes (in some cases up to 30-50 GB), being able to use BrowseEverything is essential for us. We've used the Google Drive, Box, and DropBox adapters since the beginning. Maybe a year (?) ago we started using the local file folder adapter, but with a twist that we have a bit of a monkey-patch for. For users with many files or extremely large files to upload, we allow files to be transferred via Globus into user-specific upload directories. We have a monkey-patch on BrowseEverythingController to configure the file system adapter at run-time to access a particular user's specific local file directory.

Incidentally, if there is a fork that we should look at using if the rest of the community is moving to it, we'd be open to hearing about it.

[JulieWinchester]

The README still says b-e is supposed to work with bootstrap 3 and 4 -- but maybe nobody is actually doing that and I don't know if it really does?

Should we adjust README to no longer say 3, if we're doing this?

I wonder if it would still work in Bootstrap 3 even if this is removed, since the disabling functionality seems mostly duplicated by the other code in the method? But I haven't tested it.

As a side note, we had no problems with b-e when MorphoSource was running on Hyrax 2.x or 3.x with Bootstrap 3, and we've only encountered this problem as we made the jump to Hyrax 5 and Bootstrap 4.