netbsd-wtf wmutils-core: use alternatives for bin/wtf

[anddam]

Avoid clash between two packages and let the user choose wtf they want.

General

• This is a new package and it conforms to the quality requirements

Have the results of the proposed changes been tested?

• I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
• I generally don't use the affected packages but briefly tested this PR

[Duncaen]

Alternatives are generally for programs that provide the same functionality, not to resolve conflicts.