feat: remove template and error handler source types

[lburgazzoli]

This PR is aimed to explore what we can remove from the camel-k runtime in order to ease the migration of the remaining code in this repo to camel-quarkus and in particular I'm focused on removing the specific source types we have introduced in camel-k long ago.

1. templates: all the DSLs now have support for routes templates so it is not more needed to have a wrapper that can turn a standard route in a template
2. error handler: the YAML DSL has now native support for global error handler and as we are using this errror handler source type exclusively to support kamelet bindings, then I think, we can remove the custom source type and use what is provided by the YAML DSL

There is still an issue that is related to the order on which routes are loaded but this can be explored on the apache camel side.

@squakez @davsclaus what do you think ?

Release Note

NONE

[oscerd]

Do we need this before releasing the next version?

[lburgazzoli]

Do we need this before releasing the next version?

No, it needs some adjustments on camel-k ad camel to work properly so, next release maybe

[squakez]

Look good to me. However it will need a rework on how KameletBinding error handlers are managed in Camel K as well (it will be for good as it make it explicit something that is quite hidden right now). As soon as this is ready and merged, we can make some local development/test with the snapshot before the Camel K release.