Add Signal Operators and avoid Metastability issues

[timonkrebs]

An idea I would like to implement is an idea from @mfp22 for signal operators (https://stackblitz.com/edit/stackblitz-starters-tvvtbb?file=src%2Fmain.ts) that are inspired by rxjs.

[timonkrebs]

One problem to solve is the equality in time based operators. Evaluate what other problems must be solved that come from metastable graphs Idea:

• Evaluate value on next trigger and compare these intermediate values.
• Just always compare new value to current value.
• ...

[timonkrebs]

remove equality from signal and memoizr and make it a seperate operator like filter.

[timonkrebs]

make it production ready