Add EitherT and IorT constructors from Option with monadic default

[ivan-klass]

In practice the OptionT[F, A] => EitherT[F, E, A] transformation may also require the left to be calculated as F[E]. I didn't find anything handy neither in OptionT nor EitherT having to work-around with .leftSemiflatMap(identity) like

OptionT(...) 
  .toRight(fe) // EitherT[F, F[E], A]
  .leftSemiflatMap(identity)

or

EitherT.fromOptionF(..., fe) // EitherT[F, F[E], A]
  .leftSemiflatMap(identity)

[codecov-commenter]

Codecov Report

Merging #3426 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3426      +/-   ##
==========================================
+ Coverage   91.64%   91.65%   +0.01%     
==========================================
  Files         381      381              
  Lines        8268     8278      +10     
  Branches      225      225              
==========================================
+ Hits         7577     7587      +10     
  Misses        691      691              

Flag	Coverage Δ
#scala_version_212	91.64% <100.00%> (+0.01%)	⬆️
#scala_version_213	91.44% <100.00%> (+0.01%)	⬆️

Impacted Files	Coverage Δ
core/src/main/scala/cats/data/EitherT.scala	98.53% <100.00%> (+0.02%)	⬆️
core/src/main/scala/cats/data/IorT.scala	97.84% <100.00%> (+0.06%)	⬆️
core/src/main/scala/cats/data/OptionT.scala	96.15% <100.00%> (+0.06%)	⬆️

---

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 c067cac...74a6bc0. Read the comment docs.

[LukaJCB]

Awesome, thanks!

[kailuowang]

Option, like several other data types, already has a liftTo[F] that can "lift" it into any F[_] with an ApplicativeError[F], which is the case for both IorT and EitherT.
For lifting to the left side, I believe we had a PR adding a raiseTo[F] but somehow I couldn't find it anymore.
I am thinking that instead of adding n - 1 methods to n datatypes to support transformation between we can just add a liftTo[F] and a raiseTo[F] to n data types?
In this example, we can add those to OptionT and F[Option]

update: I found the raiseTo PR #3358

[kailuowang]

can you address my last comment?

[kailuowang]

Hi, @ivan-klass , sorry about the confusion, but another maintainer merged this PR while I was drafting the feedback. We are reverting the merge, would you mind resubmit this PR? I can re-add my feedback there. Thanks!

[ivan-klass]

Sure, will re-submit with addressed suggestion