This PR adds the ability to add simple root level flags to control Lagoon cli's behaviour.

This is to be used, initially, to flag experimental behaviours.

it adds a "Flags" array of strings to the root of the config

current: amazeeio-clusterN
flags:
  - experimental
default: amazeeio-clusterN

This can be accessed via the function func (c *Config) IsFlagSet(flag string) bool attached to the Config object, which checks flag names, provides some measure of indirection, and is case insensitive.