[ENHANCEMENT] Add proper way of parsing arrays

[vnenkpet]

Parse comma-separated values into arrays.

Currently it's only possible to do with stringified JSON array

LOG_LEVELS=["error","warning"]

@Env<string[]>('LOG_LEVELS', {parseJson: true)
readonly logLevels: string[]

This should work too:

LOG_LEVELS=error,warning

@Env<string[]>('LOG_LEVELS', {parseArray: true)
readonly logLevels: string[]

We should maybe also add custom delimiters:

@Env<string[]>('LOG_LEVELS', {delimiter: ';'})
readonly logLevels: string[]

[otavlna]

implemented in #6