Choose encryption algoritm based on cert name

In [this][1] article the author presents a way to have Nginx work
with both RSA and ECC keys at the same time. This is achieved by
just including two `ssl_certificate[_key]` lines which points to
different files. By then ordering the `ssl_ciphers` in your
preferred way you can have Nginx automatically use the correct RSA
or ECDSA key/certificate.

In the article the author add ".ecc" to the files using ECDSA (ECC
is underlying technology), and ".rsa" to those using RSA. So to handle
this in our script we have a regex that checks if it can match once of
these alternatives.
All of these may appear anywhere in the `cert-name`:

    -rsa
    .rsa
    -ecc
    .ecc
    -ecdsa
    .ecdsa

All of these are also case insensitive. Having these somewhere in the
name will override the `USE_ECDSA` environment variable, so special
cases like this can be made. If the "rsa" string is matched an RSA key
is created, while the others will be of the ECDSA type.

[1]: https://medium.com/hackernoon/rsa-and-ecdsa-hybrid-nginx-setup-with-letsencrypt-certificates-ee422695d7d3

Author: JonasAlfredsson

src/scripts/run_certbot.sh

@@ -70,8 +70,18 @@ get_certificate() {
 for conf_file in /etc/nginx/conf.d/*.conf*; do
     for cert_name in $(parse_cert_names "${conf_file}"); do
         # Determine which type of key algorithm to use for this certificate
-        # request.
-        if [ "${USE_ECDSA}" == "1" ]; then
+        # request. Having the algorithm specified in the certificate name will
+        # take precedence over the environmental variable.
+        if [[ "${cert_name,,}" =~ ^.*(-|\.)ecdsa.*$ ]]; then
+            debug "Found variant of 'ECDSA' in name '${cert_name}"
+            key_type="ecdsa"
+        elif [[ "${cert_name,,}" =~ ^.*(-|\.)ecc.*$ ]]; then
+            debug "Found variant of 'ECC' in name '${cert_name}"
+            key_type="ecdsa"
+        elif [[ "${cert_name,,}" =~ ^.*(-|\.)rsa.*$ ]]; then
+            debug "Found variant of 'RSA' in name '${cert_name}"
+            key_type="rsa"
+        elif [ "${USE_ECDSA}" == "1" ]; then
             key_type="ecdsa"
         else
             key_type="rsa"