LogCLI instant queries always starts from now

[rsteneteg]

Describe the bug
When doing instant queries using the logcli client, it passes the timestamp using a parameter called start to Loki, but loki expects that parameter to be named time, so Loki defaults to use now as the start time.

To Reproduce
Steps to reproduce the behavior:

1. Run LogCLI with an instant query in the past, query will go backwards from now

Expected behavior
Logcli should use the provided timestamp and walk backwards from that time, instead of from now

Environment:

• Infrastructure: laptop
• Deployment tool: n/a

Screenshots, Promtail config, or terminal output
If applicable, add any output to help explain your problem.