Add bxl-x-twitter.svg

[Kiansa]

I've used the official X brand kit, scale it down and gave padding to the canvas to match other Boxicons logos for consistency.
there is an open PR #642 which replaces the twitter logo but this PR adds the new X logo. this way user will have access to both icons.

it should close below issues:

• request x-twitter #908
• New Twitter / X icon #897
• Request X(formerly known as twitter) icon #888
• Require icon for X, previously twitter #885
• X #863
• x/twitter icon #842
• twitter new logo (X) #815
• New Twitter (X) icon #814
• request for add icon #806
• can you add x icon (twitter)? #803
• X (Twitter) New Logo #780
• hi please add icons #770
• New twitter ( X )  #766
• X icon #758
• x-twitter #724
• Twitter X #710
• twitter x #706
• Icon for 'X' formerly twitter #689
• X icon request #683
• New Icon Request #656
• Twitter logo #651
• add x (twitter) app logo #587
• x.com #576

[BEllis]

Ths viewbox isn't right. I've scaled it to fit the normal 0 0 24 24 viewbox but had to manually center it so padding might be out,

<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" >
  <path d="M 13.308 10.882 L 19.751 3.395 L 18.224 3.395 L 12.63 9.897 L 8.162 3.395 L 3.008 3.395 L 9.764 13.228 L 3.008 21.08 L 4.534 21.08 L 10.442 14.213 L 15.161 21.08 L 20.314 21.08 L 13.308 10.882 Z M 11.215 13.314 L 10.531 12.334 L 5.086 4.543 L 7.43 4.543 L 11.826 10.83 L 12.51 11.811 L 18.225 19.983 L 15.879 19.983 L 11.215 13.314 Z"></path>
</svg>