Remove Xlayer related unused files

[GitGuru7]

Description

Resolves #

Checklist

• I have updated the documentation to account for the changes in the code.
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a test preventing this bug from silently reappearing again.
• My contribution follows Venus contribution guidelines.

[github-actions]

Package	Line Rate	Branch Rate	Health
contracts	100%	100%	✔
contracts.Admin	88%	41%	✔
contracts.Comptroller	100%	90%	✔
contracts.Comptroller.Diamond	95%	64%	✔
contracts.Comptroller.Diamond.facets	76%	64%	➖
contracts.Comptroller.Diamond.interfaces	100%	100%	✔
contracts.DelegateBorrowers	100%	89%	✔
contracts.Governance	68%	45%	➖
contracts.InterestRateModels	74%	59%	➖
contracts.Lens	45%	37%	❌
contracts.Liquidator	83%	60%	✔
contracts.Oracle	100%	100%	✔
contracts.PegStability	88%	84%	✔
contracts.Swap	88%	58%	✔
contracts.Swap.interfaces	100%	100%	✔
contracts.Swap.lib	81%	55%	✔
contracts.Tokens	100%	100%	✔
contracts.Tokens.Prime	96%	72%	✔
contracts.Tokens.Prime.Interfaces	100%	100%	✔
contracts.Tokens.Prime.libs	90%	76%	✔
contracts.Tokens.VAI	81%	53%	✔
contracts.Tokens.VRT	20%	9%	❌
contracts.Tokens.VTokens	64%	47%	➖
contracts.Tokens.VTokens.legacy	0%	0%	❌
contracts.Tokens.XVS	19%	8%	❌
contracts.Utils	50%	30%	❌
contracts.VAIVault	50%	45%	➖
contracts.VRTVault	49%	36%	❌
contracts.XVSVault	64%	50%	➖
contracts.lib	89%	71%	✔
Summary	62% (3346 / 5369)	46% (1246 / 2736)	➖