[charm-dev] Write kube config file as regular user

[sed-i]

• Before this change, the ~/.kube/config file is created and owned by root, so not readily available for apps to use. This PR writes the file as the default user (ubuntu).
• Remove the test-sa workaround, now that with uk8s 1.24 causes the cloud-init to hang on No resources found in default namespace.
• Drive-by fixes:
  • use the new jammy
  • increase timeout (launch failed: The following errors occurred: timed out waiting for initialization to complete)
  • add k as alias to kubectl
  • support more terminals ootb

[sed-i]

Ready for review, @townsend2010. cc: @Abuelodelanada

[townsend2010]

bors try

[bors[bot]]

try

Configuration problem: bors.toml: not found

[townsend2010]

bors try

[bors[bot]]

try

Build succeeded:

• Bors

[bors[bot]]

Build succeeded:

• Bors