[IMPROVEMENT] support config file for defaults

[hi-ko]

alfresco-ssl-generator should support a config file to store defaults and custom overwrites to avoid passing everything as parameters e.g.

~/.alfresco-ssl-generator/DEFAULTS

SSL_BASE=/opt/alfresco/alf_data/ssl
SSL_KEYSTORE=$SSL_BASE/keystore

ALF_CA_CN_NAME=Custom Alfresco CA
ALF_REPO_CN_NAME=Custom Alfresco Repository
ALF_SOLR_CN_NAME=Alfresco Solr
ALF_REPO_CLIENT_CN_NAME=Custom Alfresco Repository Client
ALF_SOLR_CLIENT_CN_NAME=Custom Alfresco Solr Client
ALF_OU=Unknown
ALF_L=Maidenhead
ALF_O=Alfresco Software Ltd.
ALF_ST=UK
ALF_C=GB

# server names, to be used as Alternative Name in the certificates
ALFRESCO_SERVER_NAME=localhost
SOLR_SERVER_NAME=localhost

KEY_SIZE=4096
KEYSTORE_TYPE=JCEKS # (PKCS12, JKS, JCEKS)
TRUSTSTORE_TYPE=JCEKS # (JKS, JCEKS)

# Default password for every keystore and private key
KEYSTORE_PASS=keystore
# Default password for every truststore
TRUSTSTORE_PASS=$KEYSTORE_PASS

# Encryption secret key passwords
ENC_STORE_PASS=$KEYSTORE_PASS
ENC_METADATA_PASS=$KEYSTORE_PASS

KEY_SIZE=4096
KEY_ALG=RSA

META_KEYSTORE_KEY_ALG=AES
META_KEYSTORE_KEY_SIZE=256

~/.alfresco-ssl-generator/CUSTOM

KEYSTORE_PASS=myverysecretPW!
TRUSTSTORE_PASS=$KEYSTORE_PASS
ENC_STORE_PASS=$KEYSTORE_PASS
ENC_METADATA_PASS=$KEYSTORE_PASS