imc module enhancements

[joeygo]

Pre-Submission Checklist

• [V] Commit message has the format required by CONTRIBUTING guide
• [V] Commits are split per component (core, individual modules, libs, utils, ...)
• [V] Each component has a single commit (if not, squash them into one commit)
• [V] No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• [V] New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• [V] PR should be backported to stable branches
• [V] Tested changes locally
• Related to issue #XXXX (replace XXXX with an open issue number)

Description

I modified the imc module as follows:

1. propagate content-type header
2. add the option to modify member role
3. added support to db_mode. all changes are synch to db in case db_mode is set to 2.

[miconda]

Thanks!