feat：grafana pyroscope-datasource/panel plugin supports custom HTTP headers

[scottzhlin]

Currently, pyroscope-datasource plugin only supports the configuration of instance url, while the pyroscope-panel plugin can only configure FlameQL query statement. However, in the actual running scenario of pyroscope, there may be a gateway, and header parameters need to be specified. Similar garfana prometheus plugins support custom HTTP header settings.

Therefore, plugins can support the ability to configure custom headers and query parameters.