Support for CLI command completions

[juhoinkinen]

Adds support for tab-key completions for commands, options and project id and vocabulary id parameters via Click mechanism.

A user needs to enable the support as instructed in README.md, i.e. by sourcing the completion script, either manually for every terminal session or automatically for all new sessions by the sourcing the script in a shell startup file (instructed to use .bashrc).

To produce the completion script the annif completion CLI command is added. This seems to be the standard way that many CLI tools use: pip, dvc, helm.

Implements #684.

[codecov]

Codecov Report

Patch coverage: 98.48% and project coverage change: +0.01 🎉

Comparison is base (c6daf56) 99.61% compared to head (35bc222) 99.63%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #693      +/-   ##
==========================================
+ Coverage   99.61%   99.63%   +0.01%     
==========================================
  Files          89       89              
  Lines        6166     6222      +56     
==========================================
+ Hits         6142     6199      +57     
+ Misses         24       23       -1     

Impacted Files	Coverage Δ
annif/cli_util.py	98.87% <90.90%> (-1.13%)	⬇️
annif/cli.py	99.64% <100.00%> (+0.01%)	⬆️
tests/test_cli.py	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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[juhoinkinen]

The completion response is not very instantaneous but quite usable. On my laptop annif --help and annif --version take 0.6-0.7 s, but I think the completion response is a bit faster.

I tried to optimize startup speed by moving some import statements into functions in cli.py and elsewhere. This cut annif --version time in half but did not affect annif --help and seemed not to affect completion response time. :(

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[juhoinkinen]

The completion response is not very instantaneous but quite usable. On my laptop annif --help and annif --version take 0.6-0.7 s, but I think the completion response is a bit faster.

I tried to optimize startup speed by moving some import statements into functions in cli.py and elsewhere. This cut annif --version time in half but did not affect annif --help and seemed not to affect completion response time. :(

The response time of completions will be improved by #696 to ~0.3 seconds or slightly less.