[Feature] Add timeout argument to Wait For Alert

[MoreFamed]

Is your feature request related to a problem? Please describe.
I sometimes want to wait for alerts for different times. The cause of the difference is whether I know the alert has to appear (and thus I want to wait even for a longer time) versus it needs not to appear (and I want to wait for it just for a very short time).

Describe the solution you'd like
I'd like Wait For Alert keyword to have timeout argument, like almost all waiting keywords have.

Describe alternatives you've considered
The only workaround I know about is to set default timeout value before Wait For Alert runs and set it back again afterwards. It seems very inconvenient to me.

[Snooz82]

fixed in #3245