Unlock globals during create/delete ops

[jphickey]

Is your feature request related to a problem? Please describe.
For a number of resource create/delete operations, they may take some non-deterministic amount of time to execute in the system, and may require obtaining some type of mutex in the underlying C library too (e.g. if something invokes malloc). This is especially true of creating and deleting tasks, which may need to malloc() memory for the stack, and need to create a new task resource in the kernel.

Because of this, OSAL should not hold its own global table mutex while the whole operation takes place, as this will also prevent other unrelated ops from completing.

Describe the solution you'd like
These operations should reserve an entry in the table but mark it as reserved, not with a normal ID (so distinct from a normal entry). It can then unlock the global table and complete the non-deterministic parts of the operation, then re-lock when complete.

Additional context
This is required for #642, already have it implemented but felt it was worth splitting into a separate issue/commit for tracking purposes.

Requester Info
Joseph Hickey, Vantage Systems, Inc.

[jphickey]

This becomes important/relevant for #642 because OS_TaskDelete will need to block the caller until the task actually exits, and OSAL should always avoid blocking while holding the mutex.