Fixes [FEATURE]: Sig Dashboard #301

[yashhash2]

Description

I created a sig dashboard which is accssible only by sig chairs and vice chairs. dashboard is accessible through both admin dashboard and through "sig-dashboard" route which can be used to change these things:
1)About
2)What we do
3)A link to events dashboard to add/modify events
4)Sig image
5)Adding/Removing Societies along with their image and Fac Advisor

Fixes # (issue)
#301

Dependencies

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Type of Change

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• Test B

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