Introduce Common/Universal scripts support to interpreter for python code reusing

[yuriyz]

Introduce Common/Universal scripts support to interpreter for python code reusing.

We need to introduce sharable/common scripts. To make it flexible and allow share scripts between one script type (e.g. only between Person Authentication) as well as between all script types. To make it easy to use we need :

1. re-design our current oxTrust representation to tree
2. introduce common types to python service, so it correctly loads them.

oxTrust: GluuFederation/oxTrust#1590

[yurem]

I offer to start from small steps to make script simpler:

1. Reusable python libs
2. Context objects
3. Same session variables in scripts.
   These 3 steps should make script smaller and allow us to merge them.

Next steps:

4. Identify which script we need to use in wizard
5. Write wizard

Also updates to API should not break old scripts. We can deprecated older API in CE 5.0

[yurem]

Wizard sample: https://techcommunity.microsoft.com/t5/Azure-Active-Directory-Identity/Announcing-the-public-preview-of-Azure-AD-support-for-FIDO2/ba-p/746362

[yuriyz]

I like these 3 steps. Re: wizard, we should think on some generic approach to generate wizard UI.
For developer it means:

• provide script template
• provide parameters (name and type) that should be used in template

With this information we should be able to generate wizard UI.

For admin it means :

• enter parameters in wizard UI -> render script.

[jgomer2001]

@yuriyz I've compiled a list of frequently used idioms in person authentication custom scripts:
commons.txt