Add branchout aliases

[maxtuzz]

Proposal
Having support for creating custom aliases means that teams can customise and extend branchout with aliases to ship and collaborate on common commands for all team members.

Possible implementation

branchout alias mvn=maven

Map branchout mvn to branchout maven

Save to ~/projects/myproj/.branchout-aliases/mvn.branchout

Aliases can then be committed to root project repo.

Inspired use case
Rolling kubernetes for local development requires a few maven properties:

branchout maven cv \
    -DskipTests=true \
    -Dmaven.test.skip=true \
    -Dmaven.site.skip=true \
    -Dtile-deploy.javaVersion=11-debug \
    -Ddocker.tag=$IMAGE

This is defined on a few levels. Mapping this to a simple $ branchout skaffold would help keep this consistent project wide through it being centralized in git.

[stickycode]

Good idea

My preference is for Branchoutaliases in the projection directory, so its in your face a little bit. This will encourage people to look at it. Same reason the other files are not hidden.

Could also have local aliases in ~/. config/branchout/aliases or perhaps by branchout in ~/branchout/xxx/Branchoutaliases