fix files in console-and-shells folder

- completion-shell : theme => template
- i18n-shell : app => src
- upgrade-shell : for cakephp 2, so use old notations for app (no src)
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add fr community link in where-to-get-help
update upgrade shell
fix conflict
small correction in upgrade
fix small grammar
remove the fr community for now
add upgrade in keywords
change title in upgrade page
Merge pull request #1701 from cakephp-fr/3.0-console-and-shells-small-fix

fix files in console-and-shells folder