Kasan

Results 2 issues of Kasan

Squash #2422 This PR add `start date`, `due date` to issue. This PR will change GitBucket version number because of updating database schema. If this PR is merged, I will...

feature

This PR bump AdminLTE to 3.0. ### Before submitting a pull-request to GitBucket I have first: - [x] read the [contribution guidelines](https://github.com/gitbucket/gitbucket/blob/master/.github/CONTRIBUTING.md) - [x] rebased my branch over master -...