feedback: send default metrics

The patch extends feedback_daemon functionality - now it collects
default metrics if module metrics of required version (>= 0.16.0)
is installed. The metrics are sent as a part of feedback. Feedback
version is bumped.

Closes #8192

@TarantoolBot document
Title: Feedback metrics

Now tarantool collects default metrics and sends it with feedback if
module metrics of required version (>= 0.16.0) is installed. The process
can be tuned with following options:

- `feedback_send_metric` - boolean, collect and send metrics if true.
  Is set to true by default.

- `feedback_metrics_collect_interval` - number, period of metrics
  collection, in seconds. Is set to 60 by default.

- 'feedback_metrics_limit' - number, memory limit for metrics. Is set to
  1024 * 1024 (1 MB) by default.

If required metrics module is not installed or collect always returns nil,
metrics will not present in feedback.

New version of feedback = 8.