feat: add command aliases

[Codelax]

Close #947

Still need to fix completion when using an aliased namespace like scw k8s cl cre<TAB>

Ideas

• Generate alias based on commands isc = instance server create, isl = instance server list
  It creates many duplicates, we could show different alternative on completion.
• Complete alias into expanded commands scw isc<tab> ==> scw instance server create |
  Tricky to give multiple words in one suggestions depending on used shell (bash, zsh...)
• Move config to a cli.yml file in a aliases field
• Make commands easier to use

[Codelax]

• scw alias alias create l resource=instance.server.list
• scw alias alias create isl command.0=instance command.1=server command.2=list

move alias resource to config: scw config alias

[codecov-commenter]

Codecov Report

Merging #2501 (84fb56c) into master (e0efde6) will decrease coverage by 0.32%.
The diff coverage is 49.44%.

@@            Coverage Diff             @@
##           master    #2501      +/-   ##
==========================================
- Coverage   75.15%   74.83%   -0.32%     
==========================================
  Files         134      142       +8     
  Lines       26080    28207    +2127     
==========================================
+ Hits        19600    21109    +1509     
- Misses       5810     6369     +559     
- Partials      670      729      +59     

Impacted Files	Coverage Δ
internal/alias/list.go	0.00% <0.00%> (ø)
internal/alias/resource_alias.go	0.00% <0.00%> (ø)
internal/core/command.go	44.89% <0.00%> (-3.64%)	⬇️
internal/core/shell.go	10.32% <0.00%> (-0.18%)	⬇️
internal/core/validate.go	44.21% <0.00%> (-3.58%)	⬇️
internal/namespaces/autocomplete/autocomplete.go	11.14% <0.00%> (-0.19%)	⬇️
internal/namespaces/iam/v1alpha1/error.go	0.00% <0.00%> (ø)
internal/namespaces/instance/v1/custom.go	98.05% <ø> (-0.02%)	⬇️
...ernal/namespaces/instance/v1/custom_privatenics.go	88.46% <ø> (+4.67%)	⬆️
internal/namespaces/init/init.go	46.96% <35.92%> (-6.37%)	⬇️
... and 15 more

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[kindermoumoute]

Still think we should suggest to add some usefull aliases somewhere, maybe in scw init?