Bug fixed in AT certificate description

Bug fixed in AT certificate description

1) Add missing valueof() for template (value)
2) Remove duplicate group deviceSignatureHelpers

1) Add missing valueof() for template (value)
2) Remove duplicate group deviceSignatureHelpers

f_isPolygonalRegionInside (TODO)

Some logs shall be removed later
Variable initialization with null shall be removed. Used TTCN-3 isbound() function

f_waitForCertificateChain
f_askAndWaitForCertificateChain
f_isRectangularRegionsInside (TODO)

f_verifyGnSecuredMessageSignatureWithCertificate (msg, cert)
f_verifyCertificateSignatureWithPublicKey (cert, key)
f_verifyCertificateSignatureWithIssuingCertificate (cert, cert)
f_HashedId8FromSha256
f_HashedId3FromHashedId8

f_verifyCertificateSignatureWithIssuingCertificate
f_verifyGnSecuredMessageWithPublicKey
f_verifyGnSecuredMessageWithDeviceCertificate

Add HeaderFields parameter in f_buildxxx functions

f_getCertificateSignerInfo
f_askForCertificateChain (TODO)

Adding test unit to build a encode/decode a secured beacon

helpers for certificate fields retrieving