Support forceHeader param for /imp endpoint in Import page UI

[insmac]

Is your feature request related to a problem?

QuestDB tries to detect CSV's header automatically, but sometimes it fails - in that case two things happen:

• column names are wrong (f0, f1, ...)
• CSV header row is inserted as the first item in the table.

/imp REST endpoint, used beneath the hood to process the CSV file has an optional ?forceHeader=true param, that can be used to treat the first row in the file as headers at all times.

There is a very small H button (actually, looks more like a status symbol) that, when toggled, should set this param to true, but it's super hard to notice.

Describe the solution you'd like.

Add a checkbox in the UI that can be toggled on to force the first row as a header in case of problems.

[insmac]

Issue moved to the dedicated UI repository (https://github.com/questdb/ui/issues)