Filter exported point clouds by polygon layer

[uclaros]

Description

This is a #49280 followup, adding support for spatially filtering the exported point cloud layer by a polygon layer.
Also allows exporting to uncompressed LAS files.

Funded by: State of Vorarlberg and Swiss QGIS user group

[github-actions]

@uclaros
This pull request has been tagged as requiring documentation.

A documentation ticket will be opened at https://github.com/qgis/QGIS-Documentation when this PR is merged.

Please update the description (not the comments) with helpful description and screenshot to help the work from documentors.
Also, any commit having [needs-doc] or [Needs Documentation] in will see its message pushed to the issue, so please be as verbose as you can.

Thank you!

[github-actions]

@uclaros
A documentation ticket has been opened at qgis/QGIS-Documentation#7755
It is your responsibility to visit this ticket and add as much detail as possible for the documentation team to correctly document this change.
Thank you!