Remove crash-reporting

[stephenmcgruer]

The only IDL in this was marked 'exclude' in WICG/crash-reporting#8

[stephenmcgruer]

(I have no idea if this is correct, but hopefully @foolip can tell me if/where I've made mistakes. I just searched for crash-reporting and deleted the bits that looked like they shouldn't be here).

[foolip]

You ought only need to remove the IDL files, and possibly only the one in ed/. To figure out which, you'd have to find out what files reffy would still create when run, which you do, well, by running it...

Maybe @tidoust has a more satisfactory answer for how to manage this :)

[tidoust]

A couple of comments:

1. See Do not export CrashReportBody to reffy WICG/crash-reporting#8 (comment). As things stand, Reffy will continue to extract and produce the IDL extracts, and thus will re-create the file on next run if we delete it.
2. I do not see any reason to delete the files under ed/dfns and tr/dfns. These document the definitions in the spec, which shouldn't cause any problem. If we don't want the definitions to appear, that probably means we do not want the spec to be parsed at all, in which case the spec should rather be dropped from w3c/browser-specs.

[tidoust]

I'm closing down this PR without merging. The discussion on WICG/reporting seems to have stalled for now. Dropping the files in webref will not be the right solution in any case. If something is needed on the extraction side, it will be an update in Reffy's crawling logic.