Add a "Help" page

[sophice]

Some of the new fields and sections may be a bit confusing, especially on mobile where the tooltips can't be seen. Add a help page to describe any less obvious aspects to the inputs and data, as well as some FAQs and troubleshooting. This should include;

• "Days missed" explanation
• "Days you will miss" explanation
• "Purchased tiers" explanation
• Mention that "Current tier" means the current tier you are progressing on, as displayed on the battle pass page
• Explanation of how the "projected" section works
• Explanation of how the "expected" sections work
• Explanation of how prestige tiers are handled regarding the display in the game being split up the way it is (ex. setting your tier as 120 will consider your completed tier to be rounded down to the nearest in-game display, assuming the "XP progress" you input will also match what is in the game - "45000xp" instead of "4 tiers + 5000xp"
• FAQ about why there's an "Average match XP" field and not separate fields for various XP sources