Implement missing builtins

[me-viper]

Ensure all rego built-in functions (like http.send) have implementation.

List of SDK dependent built-ins

• rand.intn
• json.match_schema
• json.patch
• json.verify_schema
• object.subset
• indexof_n
• sprintf
• strings.any_prefix_match
• strings.any_suffix_match
• regex.find_n
• regex.globs_match
• regex.replace
• regex.split
• regex.template_match
• glob.quote_meta
• units.parse
• units.parse_bytes
• base64url.encode_no_pad
• hex.decode
• hex.encode
• urlquery.decode
• urlquery.decode_object
• urlquery.encode
• urlquery.encode_object
• io.jwt.encode_sign
• io.jwt.encode_sign_raw
• io.jwt.decode
• io.jwt.decode_verify
• io.jwt.verify_es256
• io.jwt.verify_es384
• io.jwt.verify_es512
• io.jwt.verify_hs256
• io.jwt.verify_hs384
• io.jwt.verify_hs512
• io.jwt.verify_ps256
• io.jwt.verify_ps384
• io.jwt.verify_ps512
• io.jwt.verify_rs256
• io.jwt.verify_rs384
• io.jwt.verify_rs512
• time.add_date
• time.clock
• time.date
• time.diff
• time.format
• time.now_ns
• time.parse_duration_ns
• time.parse_ns
• time.parse_rfc3339_ns
• time.weekday
• crypto.hmac.equal
• crypto.hmac.md5
• crypto.hmac.sha1
• crypto.hmac.sha256
• crypto.hmac.sha512
• crypto.md5
• crypto.sha1
• crypto.sha256
• crypto.parse_private_keys
• crypto.x509.parse_and_verify_certificates
• crypto.x509.parse_certificate_request
• crypto.x509.parse_certificates
• crypto.x509.parse_keypair
• crypto.x509.parse_rsa_private_key
• graph.reachable_paths
• graphql.is_valid
• graphql.parse
• graphql.parse_and_verify
• graphql.parse_query
• graphql.parse_schema
• graphql.schema_is_valid
• http.send
• providers.aws.sign_req
• net.cidr_contains_matches
• net.cidr_expand
• net.cidr_is_valid
• net.cidr_merge
• net.lookup_ip_addr
• uuid.rfc4122
• semver.compare
• semver.is_valid
• rego.metadata.chain
• rego.metadata.rule
• rego.parse_module
• opa.runtime
• trace