Adds created and modified timestamps

[bbengfort]

Adds created timestamp to object, and adds logic to the Put command. Adds modified to each version, which is added by the version manager.

[codecov]

Codecov Report

Merging #30 (382fc6a) into main (5b2a76c) will decrease coverage by 1.07%.
The diff coverage is 11.76%.

❗ Current head 382fc6a differs from pull request most recent head c74e4e8. Consider uploading reports for the commit c74e4e8 to get more accurate results

@@            Coverage Diff             @@
##             main      #30      +/-   ##
==========================================
- Coverage   58.11%   57.04%   -1.07%     
==========================================
  Files          12       12              
  Lines         721      738      +17     
==========================================
+ Hits          419      421       +2     
- Misses        249      264      +15     
  Partials       53       53              

Files	Coverage Δ
honu.go	51.36% <100.00%> (+0.26%)	⬆️
versions.go	100.00% <100.00%> (ø)
object/object.go	63.63% <0.00%> (-12.04%)	⬇️
object/object.pb.go	14.49% <0.00%> (-0.90%)	⬇️