[Discord bot] DMP mentor cert generation, download and error message-P2

[omkar309]

Goal: Issuing certificates to contributors (both community program and DMP), mentors (for DMP) and organizations (for DMP)

User Type: DMP Mentor

Usecase:

• [x] Mentor can click on "My certificate" and based on the DPG points which ever highest milestone the user has achieved a VC will be generated
• [x] Mentor can see button next to their generated VC- Download: A PDF of the VC is downloaded onto their system (Desktop or mobile)
• [x] In case mentor does not have enough points for even the first milestone, on clicking the My certificate button the user will get a prompt in response- "Sorry based on your DPG points you are yet to achieve a milestone. Continue your DPG journey by reviewing more tickets to achieve milestones"

[KDwevedi]

Mentor points, registration, milestones etc have yet to be clarified, i.e. it is not known how mentors are distinct from contributors as entities in these regards.