[RUM Dashboard] add impactful metrics panel(JS Errors)

[katrin-freihofner]

Describe the feature:

We would like to extend the RUM dashboard with a new panel. The panel holds two sections:

• a list of JavaScript errors

JavaScript errors

This section holds:

Headline JavaScript errors + icon iInCircle

2 Stats (small):

• total number of errors in the selected timeframe
• the error rate

A table with the top 5 JavaScript errors

sorted by impacted page loads; pagination

Columns:

• error message
• impacted page loads

Design issue

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)