calendar: Make calendar secrets work if they contain hyphens

[carrythebanner]

Our auto-generated secret links are random letters and numbers only. But sometimes when we create an edit link for someone by hand, it's useful to have a more readable link like https://shift2bikes.org/addevent/edit-99999-not-very-secret. Right now, if the secret contains a hyphen as in not-very-secret only the portion before the first hyphen will be interpreted as the secret (not). The result is that the link can't actually be used to manage the event, because the event can't be updated without the correct secret.

We can just stop including hyphens in secrets as a short-term solution, but longer term it would be nice to handle those.

[carrythebanner]

See https://github.com/shift-org/shift-docs/blob/master/docs/CALENDAR_ADMIN.md for the playbook on how we currently generate links for people by hand.

[ionous]

looks to be a client side issue; note the url in the browser bar, and the json request in the console

get /api/retrieve_event.php is called by addevent.js:getAddEventForm() which is called by main.js:viewAddEventForm(eventid, secret) which is called by events.html which passes the secret it pulls from parseURL().

parseURL() is implemented in scripts.html and uses the regular expression:

var editEventRe = /edit-([0-9]+)-([0-9a-zA-Z]*)/g;

could change that to:

var editEventRe = /edit-(\d+)-([\w-]*)/g;