pm2 logs with regular expression for app names

[tnguyen14]

It would be great to have pm2 logs be able to handle a regex, such as pm2 logs /foo-.*/, similar to the restart, stop and delete commands raised in #2564

[vmarchaud]

For anyone wanting to make a PR, it should be pretty straightforward : getting this logic into this function and this one

[sidthesloth92]

@vmarchaud Have added the code for pm2 logs to accept regex for names

[vmarchaud]

Published under PM2 2.5