Add Snowy knights and Sapphire glacialis to Rellekka hunter area

What have you done in this MR?

• Fixed #935 (closed)

Source:

• source 1
• source 2

Source for spawn points:

• video 1
• video 2
• video 3
• video 4

Are there any tricky things testers should keep an eye out for?

• No.

• I have tested these changes thoroughly.

• This requires extra testing due to changes to architecture or other similarly risky changes.

• I used the Thanos Tool for any JSON edits where possible, and have attached screenshots of any changes.

• I acknowledge that this contribution will be released under the AGPL license.