Replace bioenergy stores with generators

[cpschau]

Closes #1336

Changes proposed in this Pull Request

As the Generator component is extended in https://github.com/PyPSA/PyPSA/pull/1047, it can replace the bioenergy Store components. The extension of the Generator allows for a more efficient representation of finite resources, such as biomass, by eliminating the need for storage consistency constraints. Additionally, the desired model behavior to enforce the use of unsustainable bioenergy types is addressed through the new e_sum_min attribute.

Checklist

• [x] I tested my contribution locally and it works as intended.
• [x] Code and workflow changes are sufficiently documented.