UI: Fix node socket alignment in some cases

The patch fixes some misalignments in the nodes' sockets/options
recently introduced in 26d2caee3ba0, while maintaining the original
fix for T92268.

The original fix made the top padding always of the same size; while
that works when the first row of the other node is `Socket | Socket`,
it doesn't for other more common cases, `like Socket | Node Option`,
where the text results misaligned.

Differential Revision: https://developer.blender.org/D13451

UI: Fix alignment for recently added/edited icons

The patch slightly modifies two recently added icons "FILE_BLEND" and
"CURRENT_FILE" to better align them to the pixel grid, and change the
design of "FILE_BACKUP" to avoid alignment and readability issues, as
well as avoiding the outline version of the Blender logo which violates
the official logo guidelines.

Differential revision: https://developer.blender.org/D13346

UI: draw object names in 3D viewport with full opacity

Lamp names were be almost invisible when unselected.

Differential Revision: https://developer.blender.org/D6048

UI: improve graph editor channels drawing

The channel color squares are no longer positioned under the visibility
icon, since contrast is poor. Instead they are thinner and drawn on the
left side, before the visibility icon. If the curve is hidden, the color
gets less opaque.

Differential Revision: https://developer.blender.org/D5882

UI: rename "Toggle ..." back to "Show Markers"

Change made in recent show marker refactor dc87d09b8b324

On writing docs the term "Show" makes more sense.

UI: allow to hide markers region per editor

Instead of having the option to show marker lines,
make the marker region optional.

- Added a Show Markers entry in the View menu of the animation editors.
- If the markers region is not active then the Marker menu gets hidden.
- Removed marker menu from the driver editor
and don't allow to use marker operators.

WM: remove view operators from the undo stack

VSE: open file browser sidebar by default when adding external strips

Open the file browser sidebar by default when adding Movie/Sound/Image Sequence Strips, to show the operator options.

Differential Revision: https://developer.blender.org/D6212

Reviewed by: William Reynish, Julian Eisel

UI: Fix preview frame range drawing in sequencer and driver editors

Draw preview range overlay in the video sequencer in the same way as in the other animation editors
Add color control in the theme.
Prevent overlay to be drawn in the driver editor.

Reviewed By: ISS

Differential Revision: https://developer.blender.org/D6074

VSE: add a Set frame range to Strips operator

Add operator that sets the frame range, with an option to choose the regular or the preview one, around the selected strips.

Reviewed By: ISS

Differential Revision: https://developer.blender.org/D6078