Add bash completion

[azeey]

🎉 New feature

Part of gazebosim/gz-tools#1
Used together with gazebosim/gz-tools#87

Summary

Bash completion for fuel tools

Test it

$ . install/share/bash-completion/completions/ign
$ ign fuel d<tab> 

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[iche033]

looks good to me

[azeey]

@osrf-jenkins run tests please

[codecov]

Codecov Report

Merging #329 (8ce3e4e) into ign-fuel-tools4 (fe66f33) will not change coverage.
The diff coverage is n/a.

❗ Current head 8ce3e4e differs from pull request most recent head e228503. Consider uploading reports for the commit e228503 to get more accurate results

@@               Coverage Diff                @@
##           ign-fuel-tools4     #329   +/-   ##
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  Coverage            77.72%   77.72%           
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  Files                   19       19           
  Lines                 2766     2766           
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  Hits                  2150     2150           
  Misses                 616      616