Add BridgedEngine to sync15-traits

[thomcc]

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1626128 / https://jira.mozilla.com/browse/SYNC-1033

Last commit might be all we need to do for https://bugzilla.mozilla.org/show_bug.cgi?id=1628892 / https://jira.mozilla.com/browse/SYNC-1088

I also renamed interrupt to saci-interrupt and made it manually implement errors. Failure is a really slow dependency to compile, and saved us like 5 lines, and also this is a dep very specific to our team and so it kinda should reflect that (I've always kind of hated how broad it's name was). I used saci- over as- since the latter is an english word.

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[linabutler]

I like the modernization of interrupt and the telemetry addition, this looks great!

Not to bikeshed too much 🚲🎨🏠 but how do you feel about interrupt-support as a name, to match sql-support and ffi-support? I don't mind saci-, it's just an acronym we haven't use publicly yet—but, if we start using it elsewhere, this seems totally fine!

Thanks, @thomcc!