Export CSV feature Enhancement

[sridharan-dlt]

Implemented Export CSV feature

• Added download image to the chart element in SVG format (line/bar graphs).
• Once image is clicked, exportCSV(ele) is executed. A simple function gets chart data from memory using an existing function in monkshu components and calls utils.exportCSV().
• Created a file utils.mjs in chart-box/lib - to maintain common utility functions.
• exportCSV() in utils, simply takes contents and filename as parameters, then process the data from JSON to CSV format and - download it within the function itself.
• Papaparse library added to parse data with commas and newline character(delimiters).
• Added blob to the link element and removed it at the end of the function call.

PS. Changes have been modified as per the comment in PR #35. Also synced with the latest commit.

[sridharan-dlt]

@TekMonksGitHub sir, could you please review this. As made changes according to the previous PR #35.

[TekMonksGitHub]

I am rejecting this - as I forgot to check in my theme changes. So

(1) Pull my changes. Resolve conflicts (I think just theme.json). (2) Redo the theme change - you should simply just have to point to the image, no code change should be needed.