Add list of available places

[istepic]

Description

Clients sometimes want to know which places are available before acquiring the place.

Checklist

• Original documentation for the feature already covers this PR, documented on command line, as --acquired.
• Tests for the feature, no, it's a simple change
• PR has been tested

Testing:

$ labgrid-client places
target-d-8F94FBAC4EC2DAB50539F2499000055A
target-d-8F94FBAC4EC2DAB50539F299900003D5
$ labgrid-client places --acquired
target-d-8F94FBAC4EC2DAB50539F299900003D5
$ labgrid-client places --available
target-d-8F94FBAC4EC2DAB50539F2499000055A
$ labgrid-client places --help
usage: labgrid-client places [-h] [-a] [-l] [--sort-last-changed]

options:
  -h, --help           show this help message and exit
  -a, --acquired
  -l, --available
  --sort-last-changed  sort by last changed date (oldest first)

[Bastian-Krause]

I think "available" does not really fit the labgrid lingo, maybe "released" or "unlocked" are better candidates.

[istepic]

@Bastian-Krause makes sense. Done.

$ labgrid-client places -l
target-d-8F94FBAC4EC2DAB50539F2499000055A 
$ labgrid-client places -a
target-d-8F94FBAC4EC2DAB50539F299900003D5 
$ labgrid-client places
target-d-8F94FBAC4EC2DAB50539F2499000055A 
target-d-8F94FBAC4EC2DAB50539F299900003D5 
$ labgrid-client places --released
target-d-8F94FBAC4EC2DAB50539F2499000055A 

[enkiusz]

For your consideration, an alternative would be to use:

subparser.add_argument("-a", "--acquired", action=argparse.BooleanOptionalAction, default=None)

and then have --acquired and --no-acquired options used in the loop like so:

        for name, place in places:
            if self.args.acquired is True and place.acquired is None:
                continue
            elif self.args.acquired is False and place.acquired:
                continue
            if self.args.verbose:
                print(f"Place '{name}':")
                place.show(level=1)

This approach does not entail adding a new switch which is like the opposite of --acquired