Complete BAS install support

[durera]

We have the bas role almost complete, but it's not fully integrated into the sample playbooks and there were a few remaining issues to be ironed out before it's considered ready to use

[andrercm]

@durera the remaining pieces for BAS on ROKS support is done: #43

Summary:

• Added support to retrieve ROKS ingress certs to be used within BAS setup (bascfg.yml), this was mainly the part missing on the overall implementation, so now the complete end to end BAS installation and MAS setup works fine. BAS Certs are made of 3 parts. Part 1 and Part 2 are retrieved from ROKS cluster ingress' secret .crt, and Part 3 is the ISRG X1 Root certificate (available on https://letsencrypt.org/certificates/).
• Added readme to document required exported variables and how to use this role.

Note: As discussed with Alex, this playbook does not work for Fyre, due uncertainty on how to grab ingress certs for Fyre environments. Unfortunately the secret we use on ROKS to wrap up the certificate configuration does not work the same way for Fyre environments.

With BAS major upgrade to UDS, we'll probably need to investigate further on how to automate installation process for this newer version, so not sure if worths spending much more time on supporting BAS 1.1 on Fyre as well.

[andrercm]

PR has been merged, closing this.