fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7761
### Describe Your Changes
- datadog /api/v2/logs api supports message field in json format, which
is not documented and is used by serverless extension. This PR allows
message field to be both string and object type. Also added support of
not documented timestamp field
- added `-datadog.streamFields` and `-datadog.ignoreFields` flags to
configure default stream fields for datadog logs, where there's no
alternative option to pass extra headers and query args
- added ingest `max` and `min` values of data, which are ingested using
`datadogsketches` API, which is also actively used by serverless
extensions
- use default `.` separator instead of `_` for sketches metric names
until metrics are not sanitized
This commit adds the following changes:
- Added support to push datadog logs with examples of how to ingest data
using Vector and Fluentbit
- Updated VictoriaLogs examples directory structure to have single
container image for victorialogs, agent (fluentbit, vector, etc) but
multiple configurations for different protocols
Related issue https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6632
