EVM/Node: Add lock data dir

What

Lock the data directory to prevent other processes from writing to it.

Why

Prepare the snapshot import command. We don't want to import the snapshot to this data directory while a node is running.

How

Acquire a lock on the data directory until the node stops

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR