various improvements (git, processContext, step success)

[hohwille]

• fixed NPE I got when offline because ProcessResult.out was null
• improved GitContext - instead of retrieving all branches and remotes and looking for * we can simply get current branch and default remote to simplify.
• instead of checking online status 5 or more times via expensive remote operation, simply store the result
• improve step success logging that was slightly confusing

[coveralls]

Pull Request Test Coverage Report for Build 11016007304

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 126 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.2%) to 65.927%

---

Files with Coverage Reduction	New Missed Lines	%
com/devonfw/tools/ide/context/GitContextImpl.java	45	50.99%
com/devonfw/tools/ide/context/AbstractIdeContext.java	81	60.25%

Totals
Change from base Build 10990744555:	0.2%
Covered Lines:	6045
Relevant Lines:	8827

---

💛 - Coveralls

[jan-vcapgemini]

Thanks for your fixes, looks good to me. I've added some very small questions.

[jan-vcapgemini]

Please add bugfix to changelog.

[jan-vcapgemini]

I think we should add this to our changelog too. Ready to merge though.

[hohwille]

I think we should add this to our changelog too.

Done for #650
Other changes are all internal.