Adjust telegraf.Logger to be easy to use in whole codebase

[zak-pawel]

Feature Request

• Adjust telegraf.Logger to be easy to use in whole codebase, not only inside plugins (aggregators, inputs, outputs, parsers and processors).
• Moreover, telegraf.Logger should be also injected for plugins/serializers (as it is for other type of plugins).
• https://github.com/influxdata/telegraf/blob/master/docs/developers/LOGGING.md will need to be adjusted to reflect implemented changes.
• Forbids using "log" in whole codebase (by remove rule in .golangci.yml introduced in chore: Forbids "log" package only for aggregators, inputs, outputs, parsers and processors #10191 )

[srebhan]

I think all that is needed is to move the logging facility out of models to avoid circular dependencies. Then you can just do

import "github.com/influxdata/telegraf/logger"

var log = logger.New("mycategory", "mymodule", "myalias")

log.Warnf("This might go wrong...")