automate year and alumni roles

[victorzheng02]

Summary of Changes

• When users use .set profile year, year roles will be automatically assigned/removed.

Motivation and Explanation

• Manually creating new roles for each new year is tiring and could be automated. Furthermore, we have an easy way to identify alumni since the profile feature already exists.

Related Issues

resolves #229

Steps to Reproduce

• Run .profile set
• Observe if the year is less than the current year, then you will automatically be assigned the alumni role
• Observe that if the year is within the currentYears range identified by the original ticket known as the enum "validRoleYears" on the pr, then you will get that year assigned as a role to you.
• Observe that if the year is within the currentYears range and the role does not exist, the bot will automatically create this role.

Demonstration of Changes

BEFORE:

MESSAGE SENT:

AFTER:

Further Information and Comments

[Picowchew]

I left a few comments. To make the code a bit cleaner, when logging errors, can we do throw new Error('error message here') instead, and can we remove the logging of non-errors?

[Picowchew]

I left a few more comments. There are also some merge conflicts to be resolved.

[Picowchew]

LGTM!

[Picowchew]

Replace onlyDescription with description?

[marko-polo-cheno]

is there a way to set roles for everyone so far who has done a user profile?

[marko-polo-cheno]

this else should be like... === 0 right?

[marko-polo-cheno]

i guess we never have more than 1 tho