* [single selector] added a new 'single selector' to replace the 'role editor'
* [sys admin - group - member] replaced the old 'role selector' with the new 'single selector'
* [sys admin - orgs] replaced the old 'role selector' with the new 'single selector'
* [sys admin, org admin] replaced different selectors with the new 'single selector' for users & orgs
* [share link perm selector] replaced it with the new 'single selector'
* cleaned up the code, removed multiple *-op-menu.js files,
added a common component op-menu.js
* make the 'vertical dots' icon's clickable area be 24*24
* institution member: added confirm to 'set admin'
* improved code