fix: Removal of redundant service used for communication with database

[ppawlowski]

Description

This pull request includes the following changes:

• Add database host helper function
• Update database host in main application configmap and file-server job script
• Move file-storage config map to separate file
• Adjust forge and file-storage deployments to restart if config maps have changes
• Remove ExternalName service used for communication with the database, both

Related Issue(s)

#143

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label

[hardillb]

@ppawlowski Can you resolve the conflict on this please and I'll have a look