Issue #1058 period bounds

[luitjansl]

Fixes #1058

Description

When importing models from imod5 we want to import the period data as well- specifically for ghb, drn and riv. This PR implements importing period data for these packages. Moved the function expand_repetitions to make it accessible from the packages that use it.

Checklist

• [X] Links to correct issue
• [ ] Update changelog, if changes affect users
• [X] PR title starts with Issue #nr, e.g. Issue #737
• [X] Unit tests were added
• [ ] If feature added: Added/extended example

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud