[tvmc] Introduce 'tune' subcommand (part 3/4) (#6537)

[tvmc] Introduce 'tune' subcommand (part 3/4) (#6537)

* tvmc: introduce 'tune' subcommand (part 3/4)

 * introduces a subcommand to drive auto-tuning

Co-authored-by: Matthew Barrett <matthew.barrett@arm.com>
Co-authored-by: Luke Hutton <luke.hutton@arm.com>
Co-authored-by: Giuseppe Rossini <giuseppe.rossini@arm.com>
* [tvmc] address code review comments

* adjust --min-repeat-ms default value logic

* re-arrange rpc arguments to be --rpc-tracker=hostname:port and --rpc-key=str

* use a local reference of the tvmc logger

* add --target-host, default to llvm

Co-authored-by: Matthew Barrett <matthew.barrett@arm.com>
Co-authored-by: Luke Hutton <luke.hutton@arm.com>
Co-authored-by: Giuseppe Rossini <giuseppe.rossini@arm.com>