Implement ibek support develop

[gilesknap]

This is a feature to allow a dev to make changes to a support module inside of a generic ioc container.

It will work like this:-

• copy out the chosen support module to the /repos folder (mounted to the superfolder of our project)
• or allow the user to specify an existing version of a support module in /repos
• change the file /epics/ioc-xxx/RELEASE to add in the new support module path (add some comments inline to remind the dev what they are doing)
• global configure RELEASE will include this file at the end to override the internal support module path

This means rebuilding the devcontainer will still use the /repos support.

@coretl should the ioc-xxx/RELEASE file be in .gitignore ? - probably not. Then if you change an IOC and its support in parallel you will get a clear indication why the CI fails.

[coretl]

I'm not sure to be honest, leave it out until we have a reason to ignore it...

[GDYendell]

Can I suggest ibek support develop? IMO workon is unclear.

[gilesknap]

yep that sounds better

[gilesknap]

in #136 I suggest using symlinks instead of updating /epics/ioc-xxx/RELEASE but the latter is preferred as it changes the repo so that it breaks in more obvious ways if you push it before completing the support module changes (and releasing them - implying there is an 'undevelop' command too).

This also relates to #134 - because the opi files in a support module in develop mode should be editable from outside of the container and yet be discoverable from the read only opi's links.

[gilesknap]

so in #139 I have changed the name of this to
ibek dev support
to go with
ibek dev instance

The latter of which I have already implemented in ibek 1.5.2