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/shredder/download.html

@@ -14,7 +14,7 @@
             <legend>{% trans "Step 1: Download data" %}</legend>
             <p>
                 {% blocktrans trimmed %}
-                    You are about to permamanently delete data from the server, even though you might be required to
+                    You are about to permanently delete data from the server, even though you might be required to
                     keep
                     some of this data on file. You should therefore download the following file and store it in a safe
                     place: