Add IsScp to RoleExtensions

[LumiFae]

Description

Add IsScp to Role Extensions to easily check if the Role is an SCP role, I noticed there was .IsHuman and .IsAlive, but no .IsScp which could be useful to some people

What is the current behavior? (You can also link to an open issue here)

You either have to do !RoleTypeId.IsHuman && RoleTypeId.IsAlive or RoleTypeId.Team == Team.SCPs to check if the team is SCPs

What is the new behavior? (if this is a feature change)

You can now check with RoleTypeId.IsScp to see if the team is an SCP team or not.

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

No, nobody will need to change anything if they don't want to.

Other information:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentations

Submission checklist

• I have checked the project can be compiled
• I have tested my changes and it worked as expected

Patches (if there are any changes related to Harmony patches)

• I have checked no IL patching errors in the console

Other

• Still requires more testing

[VALERA771]

PR must target dev branch

[LumiFae]

@VALERA771 moved to #177