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/event/live.html

@@ -68,7 +68,7 @@
                     {% csrf_token %}
                     <input type="hidden" name="testmode" value="false">
                     <p>
-                        {% trans "Your shop is currently in test mode. All orders are not persistant and can be deleted at any point." %}
+                        {% trans "Your shop is currently in test mode. All orders are not persistent and can be deleted at any point." %}
                     </p>
                     <div class="form-inline">
                         <label class="checkbox">