Update qgis to 3.8.0

Summary:
What's new in Version 3.8 'Zanzibar'

• Expressions: Add order by support to expression aggregate and concatenation functions
• Expressions: File Information
• User Interface: Save to Template Button
• Symbology: Allow strings for font markers
• Symbology: Offset setting for point pattern fill symbol layer
• Symbology: Average line angles for marker and hashed line
• Digitising: Floating widget for advanced input next to cursor
• Digitising: Chanied add vertex at endpoint
• Forms and Widgets: Allow browsing feature list
• Analysis Tools: New aggregate method: concatenate_unique
• Processing: Add "Save layer styles into GeoPackage" option for Package Layers algorithm
• Processing: Overlap Analysis
• Processing: Allow rounding values in ExtentFromLayer
• Processing: New options to autofill batch processing dialog
• Processing: Generate raster XYZ tiles
• Processing: Join attributes by nearest
• QGIS Server: Allow configuring size for GetLegendGraphics
• Programmability: Add REGEXP SQL syntax support to spatialite provider and python connections
• Notable Fixes: Support for curves in DXF export
• 3D Features: Wide lines and polygon edge highlighting
• 3D Features: Export all frames from QGIS 3d animations as images
• 3D Features: Terrain generation from online source
• 3D Features: Configuration of field of view angle of camera

Signed-off-by: Pierre-Yves <pyu@riseup.net>

Test Plan: Launch application

Reviewers: Triage Team, JoshStrobl

Reviewed By: Triage Team, JoshStrobl

Differential Revision: https://dev.getsol.us/D6594

Former-commit-id: R2726:a8997733850e