feat: fully functionning mandatement

TODO.md

go.mod

go.sum

internal/mandate/mandate.go

internal/mandate/mandate_test.go

mailtemplate.html

pkg/franceconnect/franceconnect.go

pkg/matcher/mailtemplate.html

pkg/matcher/matcher.go

pkg/oidcserver/oidcserver.go

web/components/auth/auth.js

web/components/matcher/matcher.js

web/main.js