Add "Export Log" option in LKB UI

Two "Export" buttons should be added to the UI, one in the "Error log" accordion and one in the "Info log" accordion.

When no logs exist the button should be displayed in a "Disabled" style.

When logs do exist the button should be displayed in the "Default" style button with a tooltip:

• Export error log as JSON
• Export info log as JSON

See the mockup for examples.