adding in option to specify a custom node private key

Signed-off-by: Joshua Fernandes <joshua.fernandes@consensys.net>

README.md

@@ -36,6 +36,7 @@ All variables which can be overridden are stored in [defaults/main.yml](defaults
 | `besu_download_url` | https://bintray.com/hyperledger-org/besu-repo/download_file?file_path=besu-{{ besu_version }}.tar.gz | The download tar.gz file used. You can use this if you need to retrieve besu from a custom location such as an internal repository. |
 | `besu_install_dir` | /opt/besu | Path to install to  |
 | `besu_config_dir` | /etc/besu | Path for default configuration |
+| `besu_node_private_key_file` | "" | Path for node private key, if supplied. This needs to include the node key file name and path like so `/home/me/me_node/myPrivateKey`. If not supplied Besu will create one automatically |
 | `besu_data_dir` | /opt/besu/data | Path for data directory|
 | `besu_log_dir` | /var/log/besu | Path for logs |
 | `besu_profile_file` | /etc/profile.d/besu-path.sh | Path to allow loading Besu into the system PATH |

defaults/main.yml

@@ -11,6 +11,7 @@ besu_download_url: "https://bintray.com/hyperledger-org/besu-repo/download_file?
 besu_base_dir: "/opt/besu"
 besu_install_dir: "{{ besu_base_dir }}/besu-{{ besu_version }}"
 besu_current_dir: "{{ besu_base_dir }}/current"
+besu_node_private_key_file: ""
 besu_config_dir: "/etc/besu"
 besu_config_template: "config.toml.j2"
 besu_data_dir: "{{ besu_base_dir }}/data"

templates/config.toml.j2

@@ -2,6 +2,11 @@
 data-path="{{besu_data_dir}}"
 logging="{{besu_log_level}}"
 
+# private_key
+{% if besu_node_private_key_file != "" %}
+node-private-key-file="{{besu_node_private_key_file}}"
+{% endif %}
+
 {% if besu_network.lower() in ["mainnet", "rinkeby", "goerli", "ropsten", "dev"] %}
 network="{{besu_network}}"
 {% else %}