[java] Rename rule MissingBreakInSwitch to ImplicitSwitchFallThrough

[adangel]

That's problem 2 originally described in #2894:

I think the rule's purpose is to avoid implicit fall through to the next case, as this may be unexpected. However the rule's name
just describes its implementation strategy, and not particularly well, as fallthrough may also be avoided by continue, return and
throw statements (cases that the rule tries to handle as well).

Tasks:

• Rename the rule to ImplicitSwitchFallThrough
• Deprecated the old rule name MissingBreakInSwitch