[split] Move eclm theme to oh-my-fish/theme-eclm

https://github.com/oh-my-fish/theme-eclm

themes/eclm/README.md

-## robbyrussell
-Based on the robbyrussell theme.
-
-![robbyrussell theme](https://bachue.github.io/oh-my-fish/images/robbyrussell-screenshot.png)
-
-
-#### Characteristics
-
-* Displays git information in the command prompt when available.
-* Indicates 'master' branch with a distinctive color, encouraging the use of feature-branches (useful when development is done using pull requests)
-* If the last command was failed, the indicator would be red, otherwise it's green

themes/eclm/fish_prompt.fish

-# name: eclm
-function _git_branch_name
-  echo (command git symbolic-ref HEAD ^/dev/null | sed -e 's|^refs/heads/||')
-end
-
-function _is_git_dirty
-  echo (command git status -s --ignore-submodules=dirty ^/dev/null)
-end
-
-function fish_prompt
-  set -l last_status $status
-  set -l cyan (set_color -o cyan)
-  set -l yellow (set_color -o yellow)
-  set -l red (set_color -o red)
-  set -l blue (set_color -o blue)
-  set -l green (set_color -o green)
-  set -l normal (set_color normal)
-  
-  if test $last_status = 0
-      set arrow "$green➜ "
-  else
-      set arrow "$red➜ "
-  end
-  set -l cwd $cyan(basename (prompt_pwd))
-
-  if [ (_git_branch_name) ]
-
-    if test (_git_branch_name) = 'master'
-      set -l git_branch (_git_branch_name)
-      set git_info "$blue ($yellow$git_branch$blue)"
-    else
-      set -l git_branch (_git_branch_name)
-      set git_info "$blue ($git_branch)$blue"
-    end
-
-    if [ (_is_git_dirty) ]
-      set -l dirty "$yellow ✗"
-      set git_info "$git_info$dirty"
-    end
-  end
-
-  echo -n -s $arrow $cwd $git_info $normal ' '
-end
-