added backend task services and endpoints

[richieb21]

Notion ticket link

Admin Dash - Task Pages

Implementation description

• Added service to assign, create and list tasks

Steps to test

1. Make a user, try the endpoints

What should reviewers focus on?

• Proper permission logic when assigning tasks (Should be for admins only)
• Take a look at the current email verified logic
• Make sure only admins can access certain endpoints

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• I have run the appropriate linter(s)
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR

[YashK2005]

lgtm!