* add AlertSchedule model and relationships
change table structure to match the expected layout
* Update maint schedule map ui
* better index name
* Laravel queries
fix some issues with the ui: restricting start incorrectly and loading empty days error
* handle date limiting properly
* Another attempt add schedule constraints
* use Auth
* Update WorldMap widget to use check isUnderMaintenance
* Rename 275.sql to 276.sql
* Rename 276.sql to 277.sql
* Device Summary: don't count deleted ports
* General: prevent widget refresh while in settings (synchronize "show_settings" between frontend and backend)
* General: reduce reload flicker by delaying clearing of old content until the backend is complete.
* Port Select: exclude deleted and orphaned ports
* limit worldmap to active devices, use scope in availability map
* Linkable totals and better option description for disabled/ignored.
* fix disabled / ignore enabled display
* better? links
* style improvements. Not important enough to bump version
* fix top interfaces query
Implemented in Laravel
Doesn't use legacy PHP session
Several widgets have new features and settings, for example:
- Multiple ports in one graph
- Maps settings are configurable and override system settings but default to system settings
- Graylog stream and/or device selection
- Much improved graph widget selection
- Many more
DO NOT DELETE THIS TEXT
#### Please note
> Please read this information carefully. You can run `./scripts/pre-commit.php` to check your code before submitting.
- [x] Have you followed our [code guidelines?](http://docs.librenms.org/Developing/Code-Guidelines/)
#### Testers
If you would like to test this pull request then please run: `./scripts/github-apply <pr_id>`, i.e `./scripts/github-apply 5926`
After you are done testing, you can remove the changes with `./scripts/github-remove`. If there are schema changes, you can ask on discord how to revert.
