[web] introduce keyserver pill component
Summary:
This UI element will be repeated in several places in the keyserver selection list ui. Rather than copy + paste this logic a bunch of times, we should factor out this into a seperate + reusable component.
This is mainly a move diff; however, I did update the color variable names to follow our new color design system + made one change to the spacing between the two elements which I left a comment inline explaining
Test Plan:
Confirmed that there were no regressions with the create community modal
Reviewers: inka, michal, rohan
Reviewed By: inka
Subscribers: ashoat, tomek
Differential Revision: https://phab.comm.dev/D9905