[QGIS-Server] Enhance config cache

Add xmlDocument and server config in cache

xmlDocument and server config will be opened once for every requested W*S
Every requested W*S will point to the same server config and xmlDocument
Update cache
[processing] provide non-random default ordering of parameters in models

Fixes #11702
[processing] fixed handling of tables in models

Fixes #11694
[processing]removed unused code
[processing] fixed fields calculator algorithm

It's not a complete fix, as it just comments out a line that was causing a 'underlying C/C++ object was deleted' error
Should revisit is later. For now, this allows the algorithm to run correctly and not crash qgis
[processing] better behaviour for fields calculator custom dialog
[processing] remember last output folder in batch interface
fix nightly build (followup a57066a48d)
Merge pull request #1689 from rldhont/server_cache_project_config

[QGIS-Server] Enhance config cache
[Processing] A new tool to import data in PostGIS based on ogr2ogr and a few other ogr related fixes
Add Qt5 support
Fix some race condition segfaults of tests on exit
Formatting of tests
Return non-zero status from cmake script when build or test fails
Remove code no longer needed in QgsConfigCache
[processing] clean unused line
[processing] better output logging for gdal/org calls

Fixes #11501
[processing] Add snippet collection to script editor

The list of snippets is still very short, but the snippet management logic is added in this commit
[processing] Added missing field type to vector tools