Load filters dynamically using go plugin

[PrasadG193]

[PrasadG193]

Initial proposal document: https://github.com/PrasadG193/botkube/blob/filters-goplugin/design/dynamic-filters-loading.md

Open questions:

• Should we use volumes to store downloaded plugins?
• We can have a dedicated GitHub repo (like botkube-filters) which will contain standard plugins. And we can include these plugins as defaults in BotKube docker image. Any thoughts?

cc: @ssudake21

[pkosiec]

Thanks for the proposal! This will be continued as a part of https://github.com/kubeshop/botkube/issues/657