Add validation rules

[malikzh]

• required
• required_with
• required_without
• string
• number:[int,uint,float,ufloat]
• email
• url
• bool
• in:[]
• not_in:[]
• min
• max
• date
• time
• datetime
• regex
• starts_with
• ends_with
• contains
• alpha
• alphanum
• mime
• minlength
• maxlength