appup files inexplicably go in ebin/, not src/

Well, it's sort-of explicable: they should be available verbatim using
the Erlang interpreter's code path, and I'm not using any of the magical
rebar3 plugins for automatic appup generation.

diff --git a/amqp/src/amqp.appup b/amqp/ebin/amqp.appup
similarity index 100%
rename from amqp/src/amqp.appup
rename to amqp/ebin/amqp.appup

diff --git a/core/src/core.appup b/core/ebin/core.appup
similarity index 100%
rename from core/src/core.appup
rename to core/ebin/core.appup

diff --git a/irc/src/irc.appup b/irc/ebin/irc.appup
similarity index 100%
rename from irc/src/irc.appup
rename to irc/ebin/irc.appup