docs(CE): add managing connectors docs

[xyfer17]

Description

• add managing connectors docs

Related Issue

Relates to issue #404

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• New Connector (Destination or Source Connector)
• Breaking change (fix or feature that would impact existing functionality)
• Styling change
• Documentation update
• Refactoring
• Chore

Checklist:

• Ensure a branch name is prefixed with feature, bugfix, hotfix, release, style or chore followed by / and branch name e.g feature/add-salesforce-connector
• Added unit tests for the changes made (if required)
• Have you made sure the commit messages meets the guidelines?
• Added relevant screenshots for the changes
• Added the new connector in rollout.rb
• Have you updated the version number of the gem?
• Have you tested the changes on local/staging?
• Have you ensured that your changes for new connector are documented in the docs repo or relevant documentation files?
• Have you updated the run time dependency in multiwoven-integrations.gemspec if new gems are added
• Have you made sure the code you have written follows the best practises to the best of your knowledge?

[j0by]

I don't think adding this information in the Readme provides much of a value add. The specific step required for each connector can be quite different and ideally we should provide specific information if it is missing in the product documentation. The Readme is meant to provide a high level overview.