[split] Move ec2 plugin to oh-my-fish/plugin-ec2

https://github.com/oh-my-fish/plugin-ec2

plugins/ec2/ec2.load

-### Main program
-
-if test -d (/usr/libexec/java_home)
-  set -gx JAVA_HOME (/usr/libexec/java_home)
-end
-
-if test (/bin/ls $HOME/.ec2/pk-*.pem | /usr/bin/head -1)
-  set -gx EC2_PRIVATE_KEY (/bin/ls $HOME/.ec2/pk-*.pem | /usr/bin/head -1)
-end
-
-if test (/bin/ls $HOME/.ec2/cert-*.pem | /usr/bin/head -1)
-  set -gx EC2_CERT (/bin/ls $HOME/.ec2/cert-*.pem | /usr/bin/head -1)
-end
-
-if test -d /usr/local/Library/LinkedKegs/ec2-api-tools/jars
-  set -gx EC2_HOME /usr/local/Library/LinkedKegs/ec2-api-tools/jars
-end
-