Set EVP_CIPH_FLAG_FIPS on approved ciphers.

Support "default ASN1" flag which avoids need for ASN1 dependencies in FIPS
code.

Include some defines to redirect operations to a "tiny EVP" implementation
in some FIPS source files.

Change m_sha1.c to use EVP_PKEY_NULL_method: the EVP_MD sign/verify functions
are not used in OpenSSL 1.0 and later for SHA1 and SHA2 ciphers: the EVP_PKEY
API is used instead.