Bringing your track in line with the latest changes to Problem Specifications

[ErikSchierboom]

We're in the process of re-opening the Problem Specifications repo, as discussed in this issue.
This PR adds .meta/tests.toml files for all exercises for which canonical data is defined in the Problem Specifications repo.
We'll now discuss why we're making this change.

Keeping track of implemented tests

While most of the changes to the Problem Specifications repo are specific to that repo, there is one track-specific change:

If a track implements an exercise for which test data exists, the exercise must contain a .meta/tests.toml file.
The goal of the tests.toml file is to keep track of which tests are implemented by the exercise.
Tests in this file are identified by their UUID and each test has a boolean value that indicates if it is implemented by that exercise.
A tests.toml file for a track's two-fer exercise looks like this:

[canonical-tests]
# no name given
"19709124-b82e-4e86-a722-9e5c5ebf3952" = true
# a name given
"3451eebd-123f-4256-b667-7b109affce32" = true
# another name given
"653611c6-be9f-4935-ab42-978e25fe9a10" = false

In this case, the track has chosen to implement two of the three available tests.
If a track uses a test generator to generate an exercise's test suite, it must use the contents of the tests.toml file to determine which tests to include in the generated test suite.

Tooling

To make it easy to keep the tests.toml up to date, tracks can use the canonical_data_syncer application.
This application is a small, standalone binary that will compare the tests specified in the tests.toml files against the tests that are defined in the exercise's canonical data.
It then interactively gives the maintainer the option to include or exclude test cases that are currently missing, updating the tests.toml file accordingly.
To use the canonical data syncer tool, tracks should copying the fetch-canonical_data_syncer and/or fetch-canonical_data_syncer.ps1 scripts into their repository.
Then, running either of these scripts will download the latest version of the tool to the track's bin directory.
The tool can be run using ./bin/canonical_data_syncer or .\bin\canonical_data_syncer.exe, depending on your operating system.

Changes

In this PR, we're adding meta/tests.toml files for all the exercises for which canonical data is defined.
We've initially marked all tests as included, which means that we'll assume that your track has implemented those tests.
If there isn't anything obviously wrong with the PR, I would suggest to merge this PR first, and then later on update the meta/tests.toml files according to your track's actual implementation.