PR: Unhidden Snipers

[CoolDude034]

Adds unhidden snipers that have visible weapons attached to them and are able to rotate/look at the target
Do note, they still shouldn't be used from close and preferrably placed far away, ontop of a rooftop due to the aiming is bit weird and the weapon placement needs adjustment with cvars (tho i think it depends on the model itself).
Additionally, the sniper can be damaged by regular weapons.

This PR might be useful to use npc_sniper as an regular enemy

Convars added:
sniper_riflemodel override the weapon model to be used by the sniper, default is the AR2. You might need to mess with the x,y,z convars to get it right
sniperrifle_offset_x the 'x' offset without attachment
sniperrifle_offset_y the 'y' offset without attachment
sniperrifle_offset_z the 'z' offset without attachment
sniperrifle_offset_x_attachment the 'x' offset with attachment
sniperrifle_offset_y_attachment the 'y' offset with attachment
sniperrifle_offset_z_attachment the 'z' offset with attachment
sniperrifle_despawn_t time it takes for the prop rifle to despawn when it's out of sight
sniperrifle_use_attachment whether the rifle should be attached to an attachment point or guessing with angles
sniperrifle_attachment_point which attachment to attach to
sv_npc_sniper_use_aiming_anims if the sniper gets the bits_CAP_AIM_GUN capability
sv_npc_sniper_should_rotate_body if the sniper should rotate it's body to aim at the target
sk_npc_sniper_easy_delay the firing/paint delay on Easy difficulty

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Does this PR close any issues?

• No, it's a feature request

PR Checklist

• My PR follows all guidelines in the CONTRIBUTING.md file
• My PR targets a develop branch OR targets another branch with a specific goal in mind

Screenshots