Advanced filtering

[ebikt]

Advanced filtering, that lets user use any boolean expression of included or excluded users, teams or services.

First commit adds filtering by teams and fixes validation display in options. Other commits add advanced filtering.

[ebikt]

I must admit that I have some weird memory/cpu leaks when this is enabled (main process of chromium goes wild, process of pagerduty is OK), the problem occurs when there are some (maybe many) triggered notifications to display, I did not managed yet to reproduce the problem, but it does not occur when the plugin is not enabled. However - when the problem occurs - it does not disappear by disabling the plugin. The problem might be in pagination of results as well as in original plugin before patching. Moreover the problem occurs only on one computer. Other computer with identical chromium version (both Linux) seems to be not affected. Maybe something in user profile is interferring.

Edit: now I hit the bug with the plugin completely disabled. Thus this is not an issue of this plugin nor this particular patch.