UI - shorten Backends column headers

[hamadodene]

• "Open connections" -> "Open conn"
• "Total Requests" -> "Req"
• "Last Actvity (timestamp)" -> "Last Activity (TS)"
• "Reported as Unreachable" -> "Unreachable"
• "Reported as Unreachable (timestamp)" -> "Unreachable (TS)"
• "Last probe (status)"-> "Probe Status"
• "Last probe (timestamp)" -> "Probe (TS)"
• "Probe path" -> "Probe (path)"
• "Last probe (result)" -> "Probe (Result)"

Replacing Total requests (Req) column with "Backend successfull" and "unsuccesfull" connections ("Healthy req" and "Fail req")

Reorder them (ID, Host:Port, Open conn, Healthy req , Fail req, Status, Last Activity (TS), Unreachable, Unreachable (TS), Probe Status, Probe (TS), Probe (path), Probe (result).

[aluccaroni]

maybe we should split the issue to separate Total request in Healty Req and Fail Req?

[pv3ntur1]

maybe we should split the issue to separate Total request in Healty Req and Fail Req?

@aluccaroni 'till now we don't keep track of "Backend successfull" and "unsuccesfull" connections ("Healthy req" and "Fail req") i've just created this one to do that #219