Add show_bottom_toolbar config option

[psacawa]

Description

Same as the corresponding feature of pgcli.

Checklist

• [x] I've added this contribution to the CHANGELOG.md file.

[codecov-commenter]

Codecov Report

Merging #116 (083ffa2) into master (0baeadf) will increase coverage by 0.52%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #116      +/-   ##
==========================================
+ Coverage   62.34%   62.86%   +0.52%     
==========================================
  Files          23       23              
  Lines        1936     1982      +46     
==========================================
+ Hits         1207     1246      +39     
- Misses        729      736       +7     

Impacted Files	Coverage Δ
litecli/packages/parseutils.py	96.87% <ø> (ø)
litecli/packages/special/iocommands.py	54.51% <ø> (+3.73%)	:arrow_up:
litecli/__init__.py	100.00% <100.00%> (ø)
litecli/main.py	48.69% <100.00%> (+0.56%)	:arrow_up:
litecli/sqlexecute.py	69.16% <100.00%> (+0.25%)	:arrow_up:
litecli/config.py	85.36% <0.00%> (-4.88%)	:arrow_down:
litecli/key_bindings.py	14.58% <0.00%> (-2.09%)	:arrow_down:
litecli/clibuffer.py	33.33% <0.00%> (-1.97%)	:arrow_down:
litecli/packages/special/main.py	88.23% <0.00%> (+0.93%)	:arrow_up:
... and 3 more

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[amjith]

:+1: