#10: improve IDE support and configure workspace

[hohwille]

Implements most of #10:

• completely refactored configurator (only little left of the original code)
• integrated configurator into IdeToolCommandlet so workspace gets auto-configured before IDE is started
• pass proper arguments to eclipse
• show project name in eclipse title-bar (instead of workspace that is already shown be default)
• check if eclipse workspace is locked
• fixed bug in AbstractIdeContextTest.newContext(String, String, boolean): IdeContext was created in original location and not in the copy - hence VersionSetCommandletTest was modifying git managed file (undesired side effect).
• improved some tests
• replace last File occurrences with Path
• normalize paths in String representation (replace backslash with slash)
• make paths absolute in IdeContext (otherwise workspace configuration is not working if paths are relative)
• moved logic to resolve variables from EnvironmentVariablesResolved to EnvironmentVariables API

[jan-vcapgemini]

Looks good to me.
I've added some typo fixes and fixed log messages.
Please check the questions I've added.

[jan-vcapgemini]

Looks good to me.
I've added some typo fixes and fixed log messages.
Please check the questions I've added.

[hohwille]

@jan-vcapgemini thank you very much for your review and your constructive fixes of my typos and the log-statements I missed out to align. All your changes are correct and improve the code quality. 👍

[hohwille]

@jan-vcapgemini I finally found some minutes to address your review-comments.
Please check and see if we can resolve the remaining conversations and finally merge this.