Support custom .obsidian config directory

[r4zzz4k]

Describe the bug Recent version of Obsidian supports changing config directory from .obsidian to some custom value. For example, this is useful if one wants to have different plugin set for desktop and mobile apps, or in case synchronization software doesn't support hidden directories at all. Currently, the plugin searches for the token file in .obsidian. It should access new Vault.configDir field if it's present, falling back to default .obsidian value if that's not present.

To Reproduce Steps to reproduce the behavior:

1. Open Obsidian
2. Copy your .obsidian directory as .obsidian.desktop.
3. Open Settings
4. Open 'About' screen
5. Put .obsidian.desktop in "Override config folder".
6. Close Obsidian
7. Delete .obsidian directory.
8. Open Obsidian again. Note that the old directory is back again, the plugin created an empty file for the token. It also asks to enter the token again.

Expected behavior Plugin should search for the token file in new config directory.