Merged secure coding mode and single user mode

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Removed coding mode lesson URL constant

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Enabled secure coding

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Enabled secure coding in FailOpenAuth

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Enabled secure coding in HiddenFields

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>