Allow overriding user dir with MINICOIN_USER_DIR

Leaving config files and runtime/caches in a non-dotfile directory in ~ is a bit uncommon. Allow the user to override this to e.g. ~/.minicoin via MINICOIN_USER_DIR

assigned to @vohilshe

added 3 commits

• 9a24a2db - Don't try to process user yaml if it doesn't exist
• c253ce5a - Load user includes from minicoin directory, not HOME
• 04c0b2df - Allow overriding user dir with MINICOIN_USER_DIR

Compare with previous version

Added all the fixes into this one MR :)

The last two commits in this chain are a good idea, had complains earlier that I'm clobbering ~ with non-dot directories (I guess I'm a Windows-guy after all). And includes from the user-file should be resolved relative to ~/minicoin, yes.

The first commit is not quite right though.

added 5 commits

• 04c0b2df...893983d3 - 2 commits from branch master
• 5ec612eb - Load user includes from minicoin directory, not HOME
• 6012b3d3 - Allow overriding user dir with MINICOIN_USER_DIR
• 583d920b - Decouple user machine loading from user config existing

Compare with previous version

resolved all threads

merged

mentioned in commit eb19530f