Authorization support

[p53]

created authorization plugin support, authorization hook in processor and implemented opa authorization plugin, if somebody questioning why i didn't use schema to decode authorization infromation, it is because it would decode whole request and we don't need it for authorization we only need api key, token/user, topic, src/dst ip, we want to be fast...

[everesio]

Thank you for your contribution. I will need some time to review this PR.

[p53]

@everesio i made guide to README, i can make it even more detailed to be more easy to try

[everesio]

@p53 Could you rebase your PR on current master ?

[p53]

@everesio done

[everesio]

@p53 Your rebase / merge overwrites some changes from master. Could you rework you PR ?

[p53]

@p53 Your rebase / merge overwrites some changes from master. Could you rework you PR ?

@everesio i think i touched only code which was related to my pull request to be functional at it should not affect recent changes, but will look at it to verify

[everesio]

@p53 I guess that last rebase has overwritten some changes which were present in the master

[p53]

@p53 I guess that last rebase has overwritten some changes which were present in the master

ah ok tls-same flag did think that it was renamed from tls to same and not other way, will fix it

[p53]

@everesio - that flag fixed

[p53]

@everesio this pull request won't work, it is clashing with https://github.com/grepplabs/kafka-proxy/commit/fec23783a640a1dc4d0feb6aad9b3bfeeea54d65, will fix it

[p53]

@everesio updated that clash+fixed some bugs i found in code+improved error reporting, i made smaller pull requests for improvements/bug i found so that they can be merged sooner