Add Search Message Functionality #405

[fragm3]

Fixes #405

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream master branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

Short description of what this resolves:

Search functionality to search within messages, like done in web app

Changes proposed in this pull request:

• Add search functionality to show multiple search results

Screenshot

[fragm3]

@akshatnitd @fossasia/susi-ai please review