Add dynamic scoring feature

[yulmwu]

Implemented Dynamic Scoring (see Dynamic Value) feature.

• https://docs.ctfd.io/docs/custom-challenges/dynamic-value/
• Refs: Add dynamic scoring feature #14

[codecov]

Codecov Report

❌ Patch coverage is 80.23256% with 68 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/repo/scoreboard_repo.go	83.00%	13 Missing and 13 partials ⚠️
internal/service/ctf_service.go	69.56%	7 Missing and 7 partials ⚠️
internal/repo/scoring.go	80.00%	6 Missing and 6 partials ⚠️
internal/repo/team_repo.go	76.74%	5 Missing and 5 partials ⚠️
internal/http/handlers/handler.go	81.81%	1 Missing and 1 partial ⚠️
internal/http/router.go	0.00%	2 Missing ⚠️
internal/repo/challenge_repo.go	80.00%	1 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[yulmwu]

Test coverage is 77.55%. there is some uncovered business logic, but we believe it's safe to leave it untested.
squash merge this PR.