logcli: Add retries to unsuccessful log queries

[vyzigold]

What this PR does / why we need it:
This adds a possibility to retry unsuccessful queries when using logcli
Example output of a failed query (there is no server running on that port):

./logcli query "{type=\"logtest\"}" --addr="http://127.0.0.1" --retries 3
2021/06/22 15:28:02 http://127.0.0.1/loki/api/v1/query_range?direction=BACKWARD&end=1624368482937234835&limit=30&query=%7Btype%3D%22logtest%22%7D&start=1624364882937234835
2021/06/22 15:28:02 error sending request Get "http://127.0.0.1/loki/api/v1/query_range?direction=BACKWARD&end=1624368482937234835&limit=30&query=%7Btype%3D%22logtest%22%7D&start=1624364882937234835": dial tcp 127.0.0.1:80: connect: connection refused
2021/06/22 15:28:02 error sending request Get "http://127.0.0.1/loki/api/v1/query_range?direction=BACKWARD&end=1624368482937234835&limit=30&query=%7Btype%3D%22logtest%22%7D&start=1624364882937234835": dial tcp 127.0.0.1:80: connect: connection refused
2021/06/22 15:28:02 error sending request Get "http://127.0.0.1/loki/api/v1/query_range?direction=BACKWARD&end=1624368482937234835&limit=30&query=%7Btype%3D%22logtest%22%7D&start=1624364882937234835": dial tcp 127.0.0.1:80: connect: connection refused
2021/06/22 15:28:02 Query failed: Run out of retries while querying the server

Which issue(s) this PR fixes:
Fixes #3855

Special notes for your reviewer:

Checklist

• Documentation added
• Tests updated

[CLAassistant]

All committers have signed the CLA.

[ronensc]

Thanks for adding this feature

[sandeepsukhani]

Just added a minor suggestion but otherwise the code LGTM!
Thanks for the PR!

[sandeepsukhani]

If a user sets the retries flag value to 0 by mistake then they would unexpectedly skip making any calls. Also, retried calls should be the ones done after seeing a failure in the initial call, so let us initialise the retries above to c.Retries + 1.
What do you think?

[vyzigold]

You are right, but I enhanced your idea a little bit. I renamed the variable to "attempts", which seemed like a better name to me now. I implemented your suggestion, so attempts = c.Retries + 1 and I made the default value for c.Retries = 0. So there still is 1 attempt unless the user sets the retries flag to something other than 0.

[sandeepsukhani]

LGTM!