Extend the task filter syntax with a way to exclude terms

[cb109]

Is your feature request related to a problem? Please describe.

We do have one task that is executed like a thousand times a minute on celery, and then a few other tasks that are executed via user actions, so way less often. I can filter those one by one, but would rather be able to exclude the frequent task via search instead, but there is no syntax for it.

Describe the solution you'd like

On search engines like Google there is an optional exclude prefix, the minus sign. Example:

• Searching for django flower VS searching for django flower -pypi

The same goes for GitHub's search syntax that flower's is based on:

• https://docs.github.com/en/free-pro-team@latest/github/searching-for-information-on-github/understanding-the-search-syntax#exclude-certain-results

I'd like to be able to use that syntax to filter tasks in flower, e.g. -please_exclude_this but_include_this or -kwargs:please_exclude_this kwargs:but_include_this etc.

I'm willing to provide an implementation and a pull request if you are interested, just let me know if it's an option!