Add Clear button to Options in Dashboards

[Brian Lewis]

On clicking the Clear button, all options are set back to their defaults.

This is Null for most, the current year for selectedYear.

[Ghislain Hachey]

This is done though the choice of two way arrow md-compare could be better. Use clear or clear_all md-icon

[Ghislain Hachey]

feat(dashboard): change icon to that clears options

closes #498

→ <<cset d0075707f882>>