Power line_section relations presets and validation

[francois.lacombe]

Dear all,

Following #24456, recent power routing tagging improvements also introduce power=line_section relations.
​https://wiki.openstreetmap.org/wiki/Tag:power%3Dline_section
They are intended to merge consecutive power segments (line, cable, minor_line) into a single linear path.
Those relations only expect ways members with role line consecutively connected to each others, without branches.

It would be useful to add a preset for it and group it with power=circuit under type=power relations.

Validation could seek for branched lines or inappropriate roles.
No frequency=* or wires=* should be used on power=line_section
​https://wiki.openstreetmap.org/wiki/Proposal:Power_circuits_routing#Less_tagging_redundancy_between_lines,_sections_and_circuits

[francois.lacombe]

As in #24456, code that covers most of this ticket is available there:
​​https://github.com/open-energy-transition/validate-my-grid/commit/965f472f64e94bde1e10db5b0521724fd7598417

I look forward providing a diff here

[francois.lacombe]

Patch provided in #24456