Draft: Implements the thieving skillcape

What have you done in this MR?

• Implemented the thieving skillcape perk as according to the 2009scape website
• Fixed the skill roll calculation
• Removed the pickpocketing buff from H.A.M robes. (See tweet from JMod Ash)
• Applied the thieving skillcape perk to the pickpocket action

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

• No

• Yes, as follows:

• 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.