Suggestion: Rename repo

[liamsi]

optimint is misleading as it sounds it only supports optimistic rollups

Suggestions:

• mint-roll or mintroll
• rollmint
• Makisu (it makes the rolls; suggested by @tzdybal and my favourite so far)

[musalbas]

Or rollmint

[tzdybal]

I have no preferences, and the name won't be very visible (there's no binary). Total brainstorm (random order):

• celestia-roller
• roller
• pulley
• librollup
• celestia-rolling-kit
• celestia-rollup-kit

[tzdybal]

Final decision: rename to rollmint. Follow-up issue: #535.