Add load_dataset method to pastas

[raoulcollenteur]

Short Description

This PR adds a load_dataset method to pastas, allowing users to load predefined test datasets from the Pastas new dataset repo (https://github.com/pastas/pastas-data/tree/main). For now, only a limited number of datasets are available, but more can be added later.

Checklist before PR can be merged:

• closes issue [DEVELOPMENT] Add (synthetic) test datasets #673
• is documented
• Format code with Black formatting
• type hints for functions and methods
• tests added / passed

Usage

Simple, just type:

ps.load_dataset("collenteur_2021")

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.24% (target: +0.00%)	✅ 89.29%

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (6a7edc7)	5975	4458	74.61%
Head commit (8000aa3)	6055 (+80)	4532 (+74)	74.85% (+0.24%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#693)	56	50	89.29%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

See your quality gate settings    Change summary preferences

_{You may notice some variations in coverage metrics with the latest Coverage engine update. For more details, visit the documentation}

[dbrakenhoff]

Looks good! Simple and effective!

We can add a function to list the available datasets?

def list_datasets():
  r = requests.get(GITHUB_URL)
  return [file["name"] for file in r.json() if file["type"]=="dir"]

[raoulcollenteur]

I think PR is finished now and ready for review and hopefully merging. We can start adding data to the test_dataset as well if we want. I added aps.list_datasetsmethod 👍🏻

[dbrakenhoff]

👍