Add due_date text field to sidebar issue#show
Add ability sorting issues by due date ASC and DESC
Add ability to filtering issues by No Due Date, Any Due Date, Due to tomorrow, Due in this week options
Add handling issue due_date field for MergeRequest
Update CHANGELOG
Fix ambigous match for issues#show sidebar
Fix SCREAMING_SNAKE_CASE offenses for due date contants
Add specs for due date sorting and filtering on issues
Add margin to top of form actions
Closes#15213
Also fixes other modal inputs (like add new directory, etc)

See merge request !3841
fix bug causing the infinite scrolling in activity feeds to break when you click a link and navigate back

See merge request !3835
Discussion note icon shows up when you click on diff on touch screen
Fixes#15104
* Fix bug that stopped discussion note button from showing up on iOS
* Shifted button a few `px` to fix slight cutoff
<div>
<img src="/uploads/9d507091f33aa69ef68323386bf3a5c2/Screen_Shot_2016-04-15_at_12.08.46_PM.png" width="300px">
<img src="/uploads/a964a2a46636cbe4593abf272b5796f7/Screen_Shot_2016-04-15_at_12.11.40_PM.png" width="300px">
</div>
See merge request !3755
Fixed issue with sidebar edit links toggling anchor
This caused an issue with the page scrolling from the bottom to the top. Also stopped the dropdown links doing the same.
See merge request !3819
Removed commented text from system notes

See merge request !3836
Fixed issue with new MR form layout
Currently it is all over the place:

Now:

See merge request !3837
Fixes issue with note form inheriting text color
It was only really noticeable on dark themed diffs

See merge request !3834
add slack notifications for wiki pages
## What does this MR do?
Lets the Slack service be configured to send notifications when wiki pages are created or edited.
## Are there points in the code the reviewer needs to double check?
I'm just starting to get familiar with the Gitlab codebase and I was unsure on how to get the wiki page url to pass it to the slack message, on whether or not I needed to refactor the create/update methods for wiki pages from the controller to a service (but seemed necessary to test it better), and if I needed to add a column to the web hooks table or if the services table would have been enough. Please let me know if I should change anything and I will improve the MR, thanks for checking :)
## Why was this MR needed?
Related to #563 and fixes#4233.
See merge request !2998
Add raw build trace output
Closes#15308, #15147
Changes in the UI:
- on finished build:

- on running build:

See merge request !3767