Add extra environment variables to helm chart

[carlos-rodrigues-8x8]

What

The server.sh supports the customisation of the startup command throughout environment variables such as exec JAVA_OPTS, ARCADEDB_OPTS_MEMORY, JAVA_OPTS_SCRIPT, ARCADEDB_JMX, ARCADEDB_SETTINGS and ARCADEDB_HOME, but using the helm charts we are not allowed to set the values for those variables. The idea is to create a mechanism to add environment to the helm templates.

Why

This feature is particular useful if we need to customise different values for memory, jvm parameters or even different arcadedb settings.

How

The propose is to add a new parameter arcadedb.extraEnvironment, which is a list of name/value where we can setup the environment name and values. e.g:

arcadedb:
  extraEnvironment:
    - name: ARCADEDB_OPTS_MEMORY
      value: -Xms512M -Xmx512M

Discussion

#2306

[robfrank]

thank you very much for your contribution!