settings: De-duplicate code for managing display settings.
settings: De-duplicate code for managing display settings.

Now that we have a common framework here, there's no need for so many
copies of the channel.post logic.

rht/zulip,dhcrzf/zulip,tommyip/zulip,andersk/zulip,zulip/zulip,shubhamdhama/zulip,jackrzhang/zulip,synicalsyntax/zulip,jackrzhang/zulip,brainwane/zulip,zulip/zulip,showell/zulip,punchagan/zulip,jackrzhang/zulip,eeshangarg/zulip,tommyip/zulip,rht/zulip,hackerkid/zulip,zulip/zulip,synicalsyntax/zulip,andersk/zulip,kou/zulip,showell/zulip,tommyip/zulip,dhcrzf/zulip,punchagan/zulip,rishig/zulip,rishig/zulip,showell/zulip,dhcrzf/zulip,punchagan/zulip,zulip/zulip,eeshangarg/zulip,jackrzhang/zulip,kou/zulip,synicalsyntax/zulip,andersk/zulip,timabbott/zulip,hackerkid/zulip,showell/zulip,rht/zulip,rishig/zulip,eeshangarg/zulip,brainwane/zulip,eeshangarg/zulip,tommyip/zulip,tommyip/zulip,synicalsyntax/zulip,timabbott/zulip,brainwane/zulip,andersk/zulip,timabbott/zulip,brainwane/zulip,zulip/zulip,showell/zulip,synicalsyntax/zulip,hackerkid/zulip,synicalsyntax/zulip,hackerkid/zulip,shubhamdhama/zulip,hackerkid/zulip,tommyip/zulip,andersk/zulip,timabbott/zulip,punchagan/zulip,eeshangarg/zulip,shubhamdhama/zulip,brainwane/zulip,tommyip/zulip,rht/zulip,timabbott/zulip,rht/zulip,dhcrzf/zulip,kou/zulip,andersk/zulip,punchagan/zulip,rishig/zulip,eeshangarg/zulip,rishig/zulip,hackerkid/zulip,jackrzhang/zulip,rishig/zulip,timabbott/zulip,synicalsyntax/zulip,rht/zulip,hackerkid/zulip,punchagan/zulip,showell/zulip,kou/zulip,shubhamdhama/zulip,rishig/zulip,dhcrzf/zulip,eeshangarg/zulip,kou/zulip,brainwane/zulip,jackrzhang/zulip,dhcrzf/zulip,zulip/zulip,showell/zulip,shubhamdhama/zulip,andersk/zulip,kou/zulip,kou/zulip,shubhamdhama/zulip,zulip/zulip,punchagan/zulip,jackrzhang/zulip,dhcrzf/zulip,timabbott/zulip,brainwane/zulip,rht/zulip,shubhamdhama/zulip