Enhancement: Internal Bridge angle override

[igiannakas]

Description

Enable overriding of the auto calculated internal bridge angle for cases where the automated algorithm fails to produce adequate bridging results.

Set to 0 (default) to disable (retain the automated calculation).

Fixes #2186

Screenshots/Recordings/Graphs

Default

Override:

Tests

1. Tested with 0 value - works as expected. Automatically calculated bridge angle used
2. Tested with any > 0 set value. Works as expected
3. Used modifier on the object to set override. Works, but only if the entire bridging layer is covered by the modifier.

@Noisyfox would welcome your thoughts please on point 3. When placing a modifier it segments the region correctly but it ignores the angle provided. Unfortunately I am not very familiar with this (quite complex) code so will end up breaking something if I interfere more :) any pointers on where to look for this would be greatly appreciated :)

[laukejas]

Tested and it seems to be working without any issues.