feat: Spring cloud gateway routing

[pj892031]

Description

This PR implements routing in SCGW. The original implementation contained two ways how to route and it was required to set up this type of routing by APIML_SERVICE_GATEWAY_PROXY_ENABLED.

The new implementation support both and they are as default enabled.

The preferred routing is by header (if the header is set, this type of routing is used). Differences against the original routing by header:

• the header required localhost and serviceId. It was changed to use serviceId or apimlId (used by Gateway)
• the routing string could contain multiple steps separated by /
• the header is changed during throughput (ie. 'APIML1/APIML2' > 'APIML2' > nothing). It allows routing with infinity levels of APIML

The second way is routing by basePath. There is just one change - it allows to use APIML ID.

New APIML metadata:

• apiml.service.externalUrl
  • if this URL is defined SCGW skips the load balancer and resends request to this hostname and scheme
  • for Gateways it will be set by an external URL such as a DVIPA address
• apiml.service.apimlId
  • this value identifies an instance of APIML
  • it should be used to route between multiple APIML instances (see multitenancy and multiple GW with the same serviceId)

It also contains:

• refactor of authentication schema filters (authentication is available for both type of routing)
• fix of common method removeFirstAndLastOccurrence

Linked to #2884
Part of the #2651

Type of change

Please delete options that are not relevant.

• (fix) Bug fix (non-breaking change which fixes an issue)
• (feat) New feature (non-breaking change which adds functionality)
• (docs) Change in a documentation
• (refactor) Refactor the code
• (chore) Chore, repository cleanup, updates the dependencies.
• (BREAKING CHANGE or !) Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas. In JS I did provide JSDoc
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• The java tests in the area I was working on leverage @nested annotations
• Any dependent changes have been merged and published in downstream modules

For more details about how should the code look like read the Contributing guideline

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