Rename meta field

[elmarti]

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report
[x] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/LokiJS-Forge/LokiDB/blob/master/CONTRIBUTING.md#question

Current behavior

When storing data in LokiDb, a meta field is created which stores data about the object. This is problematic because meta is a common name and leads to collisions with other field names called meta.

Expected behavior

Meta is prefixed with something to obfuscate the field such that collisions become very unlikely. e.g $lokiMeta.

We will need to handle older data, example logic:

if dbVersion <= 1.5 then use `meta` else `$lokiMeta`

Minimal reproduction of the problem with instructions

Insert data into a LokiDb with a field called meta.

What is the motivation / use case for changing the behavior?

Reduce friction in migrating to/using Loki by allowing the use of fields called meta

Environment

All