* adds ArrayDuration and ArrayBool flags,
makes sendTimeout and tlsInsecure configurable per remoteWrite url
* added backward compatibility testcases for ArrayDuration and ArrayBool
* fixes bool flag
* fixes test cases
Array type flag is now defined as `value` type in flag description when printed.
This change adds additional description to every Array type flag so it would be
clear what exact type is used:
```
-remoteWrite.urlRelabelConfig array
Optional path to relabel config for the corresponding -remoteWrite.url
Supports array of values separated by comma or specified via multiple flags.
```