Fixed issues reported by SonarQube

JIRA ID - https://www.mulesoft.org/jira/browse/CLDCONNECT-2021
1. Fixed all the Blockers & Critical Issues
2. Resolved most of the Major, Minor & Info Issues.
3. Updated CHANGELOG.md
4. Updated Devkit to 3.5.2-SNAPSHOT

Detailed snapshot issues resolved is attached in the JIRA.