Feature: Preprocess JVM properties at app start to adjust to system environment.

[infeo]

Fixes #2838. Relates to #2885 (comment)

This PR introduces a preprocessing of JVM properties at application start to react system environments settings. The preprocessing is done in way which will be compatible with the JDK 21 preview feature of String templates.

To substitute a string in a property, it needs to be enclosed in @( ) @{} and may only contain the characters A-Z, a-z, 0-9 and _. Only the keywords appdir,appdata, localappdata and userhome are supported for now.

TODO:

• adjust buildscripts
• replace ~ by @(userhome) in code

[infeo]

After merge, issue #2853 can also be fixed.

[overheadhunter]

Can you add a test for the process function with various inputs and their expected outputs as parameters?

[infeo]

Can you add a test for the process function with various inputs and their expected outputs as parameters?

Done in 2c0474e

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I had to circumvent a problem making the situation less clean: The logDir is specified by a property, which gets resolved at class initiatlization (due to creating a logger for Cryptomator.java). I moved the PropertiesPreprocesser::run directive now to the constructor of the Environment object and initialize it also in Cryptomator.java to make it more obvious.

Addiitonally, i changed on Windows some locations from appdata to localappdata.

[overheadhunter]

I dislike the static ENV in the main class. Let's have a call to discuss alternative solutions for the initialization order problem.

[infeo]

After some suggestions from @overheadhunter, I refactored the code.

PropertiesPreprocessor is replaced a decorator of the system Properties. getProperties() is overriden to lazily substitute variables in the requested property, if it starts with cryptomator.. The main class Cryptomator.java has now a static initalizer block, in which the default system properties are replaced by its decorator via System.setProperties().

The log configuration class now directly access the decorated properties instead of Environment, because it loaded before the fully initiallization of the main class.