decode uri component before redirect for safe redirect

Bug/import

Simplify acceptance test env pipeline handler settings.

It will now inherit from common settings.

Return edit info from update_item and refactor item.py to use usage_key_with_run

Wrap JSInput Python code in CDATA section

Add defininition of window.location.origin in both studio and LMS

Python code can commonly contain characters that are invalid XML, such
as '<' and '>'. This has proven to be a pain point for instructors
implementing custom Python grading functions for their JSInput problems
(see sample code below).

This change creates a more robust template from which to make
modifications.

```python
    # This is an XML syntax error, when not inside a CDATA section.
    if i < 0:
        print('negative')
```

Use clear and send_keys instead of action chains in page object methods

Refactor studio tests to use StudioCourseTest

removing syslog_addr

This is not currently being used in production and will not
be used moving forward since logs are remoted using splunk

Improve is_browser_on_page method for Studio Container page

Unit test for import performance STUD-1994

do the import from wherever it unpacked.
Avoids an exception where the top-level dir had a subdir of same name
as one being moved, but also just makes it faster.

Ned/add test to 4080

Use a version of opaque keys that identifies version numbers in the key prefixes

Make test_export_all_courses not flaky

Bugfix: New Tab name being initialized as null

Disable failing test STUD-2003

Improve clicking and synchronization in Studio bok-choy tests

Add support for theme translations and LANGUAGE_DICT override

Add "Correct or Past Due" option for showanswer