Add RNG support to randobs

[codecov-commenter]

Codecov Report

Merging #162 (abb846c) into main (03f8fb1) will increase coverage by 0.03%. The diff coverage is 100.00%.

:exclamation: Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@            Coverage Diff             @@
##             main     #162      +/-   ##
==========================================
+ Coverage   88.50%   88.53%   +0.03%     
==========================================
  Files          15       15              
  Lines         600      602       +2     
==========================================
+ Hits          531      533       +2     
  Misses         69       69              

Impacted Files	Coverage Δ
src/randobs.jl	100.00% <100.00%> (ø)

[CarloLucibello]

let's mimick the rand etc interface and have randobs([rng], data, ...)

[EssamWisam]

let's mimick the rand etc interface and have randobs([rng], data, ...)

Alright.