Propose new alias for git branch deletion

This will add two new aliases for `git` to remove a branch.
There is an old alias `gdel` which is not named well because all "branch wise" aliases start with `gb`

So i added two new to delete the branch
`gbd` to remove fully merged branches with upstream
`gbD` to force remove a branch

aliases/available/git.aliases.bash

@@ -44,6 +44,8 @@ alias gb='git branch'
 alias gba='git branch -a'
 alias gbt='git branch --track'
 alias gbm='git branch -m'
+alias gbd='git branch -d'
+alias gbD='git branch -D'
 alias gcount='git shortlog -sn'
 alias gcp='git cherry-pick'
 alias gco='git checkout'