Add support for nodeSelector Key within Deployment manifests

[colinbjohnson]

We (and other customers) may utilize arm64 based clusters or clusters with specific types of nodes. Providing a "nodeSelector" key within deployment manifests would allow customers that run clusters of different types to control which nodes that nango pods run on.

Two notes:

• we (the client I work with) has a workaround in that they can run linux/amd64 nodes
• the specific issue we face (amd64 docker images being unable to run on arm64 nodes) could also be resolved by Build multi-arch images for arm64 nango#2376