[WiP] Separate authorization models + add Crowd

[fbelzunc]

This is a Work in Progress

This is a PR which intends two different things:

1. Separate the authorization models from the SecurityRealm
2. Add the possibility to use crowd (right now only groups by header and ldap works)

• Work progress

[ X ] Separate authorization models from the SecurityRealm
[ X ] Add crowd authorization model
[ X ] Correct findbugs
[ X ] Add readResolve to migrate the data
[ X ] Create new tests with readResolve
[ X ] More code refractor

• Notes:
• The implementation of the cache should use a different approach, but it is not my intention to fix all the plugin issues on this PR.

I am waiting for the review of the maintainer.

CC @Wadeck

[jglick]

Note that the usage of “authorization” in this plugin is nonstandard, as it is not defining an AuthorizationStrategy. Rather, this usage is a piece of authentication: looking up (e.g., LDAP) group names based on a user name.

[jglick]

Would clash more or less superficially with #40.

[jtnord]

looks like this stores a password to Crowd in plain text.

[jtnord]

@fbelzunc did you mean to use Secret here?