Add new events

[samliew]

Type of change

• Bugfix
• New Feature
• Existing Feature
• Content Change

Pre-review checklist

• I have commented my code (where applicable)
• I have checked the spelling/grammar (where applicable)
• I have checked the dates and link references (where applicable)

Brief description of the change:

Add new events JSON from Issues

• No more April Fools pranks in the foreseeable future #42 Add No April Fools
• Annual Winter/Summer Bash event cancelled indefinitely #41 Add Cancelled Winter Summer Bashes
• Beginning of the formal site sponsorship program #44 Add beginning of the formal site sponsorship program
• First usage of the sponsored tags feature seen with Adobe #47 Add sponsored tags feature
• How-To Geek partners with Stack Overflow #48 Add How-To Geek partners with Stack Overflow
• Public bookmarks have been turned into private Saves #49 Add Public bookmarks converted into private Saves
• Stack Overflow security incident #50 Add security incident
• Stack Gives Back #51 Add Stack Gives Back

Is this feature/update deployment associated with any issues?

closes #42
closes #41
closes #44
closes #47
closes #48
closes #49
closes #50
closes #51

[9ao9ai9ar]

I quickly glanced through the changes and everything seemed to be in order, but since I'm the one who generated these JSON objects through the Event Editor, it's better if it's someone else who reviewed and approved the pull request. Also, in #42 @Oaphi requested that more description be added before proceeding, to which I replied that I'm not well equipped to do so. Therefore that part may need a bit more input from other reviewers.