Replace Travis with GitHub actions and fix many typos (#1657)

* Create django.yml

* Fix working directory

* ..

* .

* ..

* a.

* ..

* .

* Fix typo

* Install hunspell

* maxfail

* Fix install

* .

* Reduce number of typos

* Even less typos

* Postgres debug

* Spelling fixes, yet again

* Postgres with PW

* Fix failing test

* New workflows

* Fix syntax error

* Install gettext

* Test aginst python 3.6 as well

* Clean up strategies

* Add badge, do not ignore migrations

* Use pip cache

src/pretix/control/templates/pretixcontrol/order/refund_process.html

@@ -20,7 +20,7 @@
         {% csrf_token %}
         <p>
             {% blocktrans trimmed with amount=refund.amount|money:request.event.currency method=refund.payment_provider.verbose_name pending=pending_sum|money:request.event.currency total=order.total|money:request.event.currency %}
-                We recevied notice that <strong>{{ amount }}</strong> have been refunded via
+                We received notice that <strong>{{ amount }}</strong> have been refunded via
                 <strong>{{ method }}</strong>. If this refund is processed, the order will be underpaid by
                 <strong>{{ pending }}</strong>. The order total is <strong>{{ total }}</strong>.
             {% endblocktrans %}