feat: themes (#902)

* chore: add next theme and initial setup

* chore: add dark mode colors to layouts

* chore: user general setting page theming

* chore: dashboard theming

* chore: project page theming

* chore: workspace setting page theming

* chore: my issue page theming

* chore: cmdk theming

* chore: change hardcode bg and text color to theme

* chore: change color name according to the design

* style: fix card in the dashboard

* style: fix merge conflict design issues

* style: add light high contrast and dark high contrast

* style: fix cmd k menu color and selection

* feat: change theme from cmdk menu

* chore: add multiple theme field to custom theme

* chore: removed custom theming

* fix: build error

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Co-authored-by: Saheb Giri <iamsahebgiri@gmail.com>