MDL-41744 Users: Convert key to value in bulk upload

Menu profile field expects value, during bulk upload if value is passed by form
then options key is passed. So converting key to value if passed though form
MDL-42143 editpdf: Convert gspath to proper setting

This will ensure we get better validation/feedback of the path.
MDL-41379 core_outcome: added some CSS to the course outcome table to make it display nice
MDL-41398 output: implemented maintenance renderer
MDL-38155 Enrolments: User can be suspended by bulk upload

Added ability to suspend user enrolment during bulk upload,
this can be done by setting enrolstatus field in csv file
MDL-38196 Backup/restore: Display log if non-empty

When doing a backup or restore operation with the normal user interface,
if there is anything in the backup/restore log, it will now be displayed
at the end of the process below the Continue button.

If you have developer debugging enabled, it sets the display level to
LOG_DEBUG and there will always be content in the log. Otherwise, it
uses LOG_INFO which generally means the log is empty, and nothing
displays (no visible change for users).
MDL-41838 Files: Implement .tar.gz packer (1 of 2)

A new packer for .tar.gz files (MIME type application/x-gzip) has been
implemented, including unit tests.

This packer is intended for use during backup/restore only and is not
otherwise exposed in the user interface at present. However, it is
supposed to follow the (ancient) POSIX .tar standard; files created
with this packer will open in GNU tar.

There are restrictions in support corresponding to the POSIX standard:

- Non-ASCII filenames are not supported.
- Very long file/path names are not supported.
- Individual files within the .tar may not be more than 8GB.

Some of these limitations might need to be addressed in future changes
if the packer were to be used in areas other than backup/restore.
MDL-41838 Backup/restore: Support .tar.gz format for .mbz (2 of 2)

The new experimental setting enabletgzbackups allows backups to be
created so that the internal format for .mbz files is .tar.gz.

Restore transparently supports .mbz files with either internal
formats (.zip or .tar.gz).

The .tar.gz format has the following benefits for backup:
- Supports larger files (no limit on total size, 8GB on single file
  vs. 4GB limit on total size)
- Compresses text better, resulting in smaller .mbz files.
- Reports progress regularly during compression of single files,
  reducing the chance of timeouts during backups that include a
  very large file.

Time performance may also be improved although I haven't done a
direct comparison.
MDL-37153 - assign: Obey grade display settings in submission status

The assignment submission status screen was ignoring the grade item's
display setting, showing scores even if it's set to display letters only.
MDL-41993 Atto: Always clean/update the textarea when the content is changed
MDL-32188 fix type in question/engine/upgrade.txt
MDL-41604 Moodle should also fallback to the default theme when a parent theme is invalid.
MDL-41940 files Fixes for behat tests

Commented out second test pending MDL-42013 visibiliy checking.
Merge branch 'MDL-32188' of git://github.com/timhunt/moodle
Merge branch 'MDL-41940' of https://github.com/merrill-oakland/moodle
Merge branch 'MDL-41993-master-fix1' of git://github.com/damyon/moodle
Merge branch '42057-26' of git://github.com/samhemelryk/moodle
MDL-42020 course: performance improvement in course listings

- better performance when get_course_count() OR search_course_count() are called by themselves
- better performance in displaying course contacts
Merge branch 'MDL-42143-master' of git://github.com/danpoltawski/moodle
Merge branch 'wip-MDL-42020-master' of git://github.com/marinaglancy/moodle