[java] initial support of Java binding

[wgtdkp]

This PR provides initial support of Java binding with SWIG.

1. separate configuration of Commissioner to Commissioner::Init, this is required by the java binding to work.
2. new CMake target commissioner-java which generate java binding of native ot-commissioner library.

• [X] cmake targets and SWIG interface file.
• [X] GitHub Action build. Depends on PR https://github.com/openthread/ot-commissioner/pull/96.
• [X] rebase on PR https://github.com/openthread/ot-commissioner/pull/95.

[codecov-io]

Codecov Report

Merging #97 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #97   +/-   ##
=======================================
  Coverage   61.18%   61.18%           
=======================================
  Files          55       55           
  Lines        5359     5359           
=======================================
  Hits         3279     3279           
  Misses       2080     2080           

Impacted Files	Coverage Δ
src/app/commissioner_app.hpp	80.00% <ø> (ø)

[codecov-commenter]

Codecov Report

Merging #97 into master will increase coverage by 23.72%. The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           master      #97       +/-   ##
===========================================
+ Coverage   38.52%   62.24%   +23.72%     
===========================================
  Files          58       58               
  Lines        5368     5369        +1     
===========================================
+ Hits         2068     3342     +1274     
+ Misses       3300     2027     -1273     

Impacted Files	Coverage Δ
include/commissioner/commissioner.hpp	43.75% <ø> (ø)
src/app/commissioner_app.hpp	80.00% <ø> (+40.00%)	:arrow_up:
src/library/commissioner_impl.hpp	100.00% <ø> (+7.69%)	:arrow_up:
src/app/commissioner_app.cpp	29.30% <100.00%> (+20.82%)	:arrow_up:
src/library/commissioner_safe.cpp	62.34% <100.00%> (+32.98%)	:arrow_up:
src/library/commissioner_safe.hpp	100.00% <100.00%> (ø)
src/app/cli/console.cpp	76.92% <0.00%> (-11.54%)	:arrow_down:
src/app/border_agent.cpp	55.88% <0.00%> (+2.20%)	:arrow_up:
src/library/coap.cpp	72.13% <0.00%> (+2.55%)	:arrow_up:
src/library/timer.hpp	100.00% <0.00%> (+3.57%)	:arrow_up:
... and 29 more

[wgtdkp]

using matrix to build on both OS ?

Seems not very necessary to me.