Simplified well completions overview

**Show well completions in a simplified scheme:**
- Wells are vertical
- Layers have identical thickness.

**Possible features:**
- a slider for the time axis, where wells appear/disappear as the slider moves?
- a multi-select filter for different layers (e.g. only show wells completed in at least one of the selected layers).
- choose how wells are distributed along "x axis".
- chronologically
- visually grouped based on formation it is completed on
- injector group / producer group / plugged group

**Data input:**
- ecl2df? (need `COMPDAT` as function of time)

**Rough hand made sketch:**

Start by locating the existing well-completion visualization entry point and reviewing how ecl2df supplies COMPDAT data as a function of time. Clarify which of the proposed slider, layer filter, and well-grouping options are in scope; done should be defined as an agreed simplified scheme with specified data input and interactions.

Written by the indexing model from the issue text.