Feature/add jinja2 support

[madeline-scyphers]

• Add jinja2 support for configs
  Jinja2 working for configs, parsed on config load
  working example of parameters and constraints from for loop in tests
• Doc updates to include jinja and fix sphinx errors

closes #128

[codecov]

Codecov Report

Merging #139 (f4dd528) into develop (3b8b5f9) will increase coverage by 0.06%.
Report is 1 commits behind head on develop.
The diff coverage is 74.07%.

@@             Coverage Diff             @@
##           develop     #139      +/-   ##
===========================================
+ Coverage    82.34%   82.40%   +0.06%     
===========================================
  Files           27       27              
  Lines         1852     1864      +12     
  Branches       319      321       +2     
===========================================
+ Hits          1525     1536      +11     
  Misses         215      215              
- Partials       112      113       +1     

Files Changed	Coverage Δ
boa/__main__.py	89.18% <ø> (ø)
boa/metrics/metrics.py	81.81% <ø> (ø)
boa/plot.py	0.00% <0.00%> (ø)
boa/wrappers/base_wrapper.py	80.82% <ø> (ø)
boa/plotting.py	76.25% <20.00%> (-1.52%)	⬇️
boa/template.py	90.00% <87.50%> (+90.00%)	⬆️
boa/config/config.py	83.33% <100.00%> (ø)
boa/wrappers/wrapper_utils.py	88.70% <100.00%> (+0.09%)	⬆️