AVSwitch and related code refactor

[IanSav]

[AVSwitch.py]

• Complete rewrite and optimization of the code.
• Remove dead code and duplicated methods.
• Use C++ helper code to reduce the Python code complexity.
• Move "config.osd" ConfigSubsection here from"StartEnigma.py" and "UsageConfig.py" here as this is where it is most appropriate.
• Raname "iAVSwitch" to "avSwitch" to better reflect its definition and usage. The old name pointed to the new name to keep old code functional.
• Use f-strings.

[StartEnigma.py]

• Remove "config.osd" ConfigSubsection definition and move it to "AVSwitch.py"..
• Remove the defunct "config.osd.language" definition and use the newer "config.misc.locale" definition. The "config.osd.language" functionality is still maintained for code that has not yet been fixed. Note that "config.osd.language" is actually a locale and not a language!

[UsageConfig.py]

• Remove "config.osd" ConfigSubsection usage and move it to "AVSwitch.py".
• Remove the now defunct "AVSwitch" import.
• Small code optimization.

[dvbci.cpp]

• Adjust the code to use the primary "config.misc.locale" definition.

[servicedvb.cpp]

• Adjust the code to use the primary "config.misc.locale" definition.

[OSDCalibration.py]

• Complete code refactor and optimization.
• Make the screen a subclass of "Setup".
• Create a smarter singular embedded screen for the user interface.

[Setup.xml]

• Create a new "OSDCalibration" section to support the new "OSDCalibration" Setup based screen.

This code and pull request is based on the effort and work of @Captain, @Jbleyel, and @IanSav.

[sonarcloud[bot]]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud