[FEATURE] Support hotreload

[lucalas]

Hi, I really appreciate your library and I'm thinking that should be really usefull if you introduce the possibility to add hot reload of the configuration.
For example:
Application is working and I want to change configuration file without restart the application, hot reload help me to achieve this goal.

[aloneguid]

I think this can be done relatively easily for files that are on local disk with FileSystemWatcher. Of course if a config is remote i.e. Key Vault it will be hard to detect changes without constantly pinging it.