7.0.0: RFC 303 Subcommands

• Adjusted location of web/config help, see xp-runners/reference#32
  (@thekid)
• Added "xp web" command in alignment with xp-framework/rfc#303
  See xp-framework/rfc#303 (comment)
  (@thekid)
• Adopted semantic versioning according to xp-framework/rfc#300 - @thekid
• Heads up: Changed HttpScriptletURL's values from util.Hashmap to
  a map. This can affect subclasses, which will need to be refactored!
  (@thekid)