Added roadmap

[tovbinm]

Related issues
We don't have a roadmap that we communicate with the community. Let's add one.

Describe the proposed solution
Added roadmap file + update a few other files.

[codecov]

Codecov Report

Merging #394 into master will decrease coverage by 1.57%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #394      +/-   ##
==========================================
- Coverage   83.66%   82.09%   -1.58%     
==========================================
  Files         337      337              
  Lines       11078    11078              
  Branches      369      597     +228     
==========================================
- Hits         9268     9094     -174     
- Misses       1810     1984     +174

Impacted Files	Coverage Δ
.../scala/com/salesforce/op/test/FeatureAsserts.scala	0% <0%> (-100%)	⬇️
...sql/execution/datasources/csv/CSVSchemaUtils.scala	0% <0%> (-100%)	⬇️
...ala/com/salesforce/op/utils/tuples/RichTuple.scala	0% <0%> (-100%)	⬇️
...ala/com/salesforce/op/readers/CSVAutoReaders.scala	0% <0%> (-100%)	⬇️
...la/com/salesforce/op/test/TestFeatureBuilder.scala	0% <0%> (-100%)	⬇️
...e/op/stages/impl/selector/RandomParamBuilder.scala	0% <0%> (-94.45%)	⬇️
utils/src/main/scala/com/salesforce/op/UID.scala	0% <0%> (-91.67%)	⬇️
...m/salesforce/op/utils/spark/OpVectorMetadata.scala	0% <0%> (-85.46%)	⬇️
...sforce/op/utils/spark/OpVectorColumnMetadata.scala	0% <0%> (-76.09%)	⬇️
...a/com/salesforce/op/utils/spark/RichMetadata.scala	15.78% <0%> (-73.69%)	⬇️
... and 42 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0c57d96...0f426e1. Read the comment docs.

[tovbinm]

Is there anything else I should add here? please feel free to comment and/or edit.

[tovbinm]

any opinions? @leahmcguire @gerashegalov @wsuchy