Add dape-on-terminated-hooks

[akurth]

This is a naive attempt to fix #46. Hook is called within dape--kill-processes and thus allows to run code upon debug session termination.

[svaante]

Hi this seams like a fine change but dape--kill-process has been removed in the last change so the disable hook needs to be placed somewhere else.

[svaante]

After some further thought maybe it's a good idea to add an global mode like suggested in #27

[akurth]

Of course! A minor mode is in any case the better option; my proposal was just a workaround for the missing mode.

[akurth]

Now that dape-active-mode-hook exists, this is obsolete. Thanks!