Add new team

[hornofj]

team name and "Team Identifier" ("team-identifier")

team identifier should be generated from the team name but the user can override the suggested indentifier, the app needs to check if the identifier is unique

[rafiki270]

that's how it works?!

[hornofj]

the identifier should be prefilled onkeyup or on onblur when filling the team name in, now the identifier is not visible

[hornofj]

moved here Einstore/Einstore#98