Enable escaping and unescaping of level parts

[CMCDragonkai]

Description

It is now possible to have arbitrary buffers as levels. So if the buffer has 0x00 or the separator byte, it is no longer a problem. We now automatically escape the separator bytes, and we also automatically escape any escaping byte too 0x5c.

Issues Fixed

• Relates WIP: Upgrading @matrixai/async-init, @matrixai/async-locks, @matrixai/db, @matrixai/errors, @matrixai/workers, Node.js and integrating @matrixai/resources Polykey#366

Tasks

• 1. Added escapeLevel
• 2. Added unescapeLevel
• 3. Updated parseKey to properly handle where 0x00 or 0x5c may appear within the level part
• 4. Removed ErrorDBLevelSep and checkSepLevelPath and checkSepKeyPath.

Final checklist

• Domain specific tests
• Full tests
• Updated inline-comment documentation
• Lint fixed
• Squash and rebased
• Sanity check the final build