Add proper docs for full usage

[TwitchBronBron]

We need proper documentation for:

• how to use the new CLI
• how to use the programmatic APIs
• migration guide from v3 to v4

[MilapNaik]

• calling node API no longer loads JSON,
• no more bsconfig.json, only rokudeploy.json
• name changes like .. also some have been removed and need to be called manually
• talk about why changes were made in v4
• new default file array
• anything else that a dev might need to change when upgrading

[MilapNaik]

#162

[MilapNaik]

#166