Move field validate error phrases into Admin Language Pack

Right now phrases, related to form validations errors (e.g. "Field is required", "Field value isn't unique", etc.) are scattered between Theme's and Admin's Language Packs and some of them have "la_" prefix, while others have "lu_" prefix.

This becomes a serious problem, when creating website not based on advanced theme and having it's huge language pack already imported.

I propose, that we:

locate all phrases related to form validation errors
rename them to start with "lc_error_"
move to admin's language pack

Here are some phrases I've found:

la_text_sess_expired
lu_captcha_error
la_error_RequiredColumnsMissing
la_error_unique_category_field
la_error_TemplateFileMissing
la_error_OperationNotAllowed
la_InvalidState
la_invalid_state
lu_passwords_too_short
la_passwords_do_not_match
lu_passwords_do_not_match
lu_passwords_too_short
la_passwords_too_short
la_EmptyFile
la_ExportFolderNotWritable
la_error_InvalidOption
lu_ferror_review_duplicate
la_error_InvalidFileFormat
la_error_FileTooLarge
la_error_cant_save_file
la_error_MessagesListReceivingFailed
la_err_required
la_err_unique
la_err_value_out_of_range
la_err_length_out_of_range
la_err_bad_type
la_err_invalid_format
la_err_bad_date_format
la_err_primary_lang_required
la_error_UserNotFound
lu_comm_MustAgreeAffiliateTermsError
la_error_CantOpenFile
la_error_NoMatchingColumns
la_error_NoInheritancePossible
la_invalid_email
lu_email_already_exist
la_error_UnknownSection
la_err_invalid_format
la_error_ParsingError
la_error_GroupNotFound
la_error_InvalidFileFormat
la_error_FileTooLarge
la_error_cant_save_file
la_error_InvalidItemPrefix
la_error_InvalidFieldName
la_invalid_email
la_error_ConnectionFailed
la_error_MessagesListReceivingFailed
la_error_LoginFailed
la_error_EmailTemplateBodyMissing
la_invalid_integer
la_ToDateMustBeGreaterThanFromDate
lu_ferror_forgotpw_nodata
lu_ferror_unknown_username
lu_ferror_unknown_email
lu_ferror_reset_denied