Add support for Data Tiering

[monrax]

Datanode should support Data Tiering. The required values are detailed here: https://go2docs.graylog.org/current/setting_up_graylog/data_node_configuration_file.htm#s3

i.e. path_repo, as well as all s3_* parameters.

[williamtrelawny]

Please make sure to include node_search_cache_size as well.

[williamtrelawny]

nvm looks like we already are:

graylog-helm/graylog/values.yaml

Line 155 in 1e993f6

nodeSearchCacheSize: "10gb"