benchmarking-cli: add --list-pallets and --all options (#3395)

closes #2844 

- adds `list-pallets` option which prints all unique available pallets
for benchmarking
```bash
./target/release/node benchmark pallet --list=pallets
```
- adds `all` option which runs benchmarks for all available pallets and
extrinsics (equivalent to `--pallet * --extrinsic *`)
```bash
./target/release/node benchmark pallet --all
```

- use the `list=pallets` syntax in `run_all_benchmarks.sh` script

cc ggwpez

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Co-authored-by: Bastian Köcher <[email protected]>