This commit cleans up the design of setting page and
remove the inconsistency in the page design.
Few changes -
* Update the border-radius to 4px for all the buttons
* Better button UI
* Improve the layout of the setting page
* Cleaner toggle switch
This PR uses resolveProxy to read system proxy settings and store
them in proper proxy format string using ConfigUtil. It removes the previous
use proxy option and replaces it with use system proxy and manual proxy
options.
Fixes: #296.