Fix #71, Remove all only from telemetry pipe

[skliper]

Describe the contribution
Fix #71 - updated remove all to only remove Tlm_pipe subscriptions

Remove all was also removing subscriptions
from the command pipe, which leaves TO
inoperable. The remove all command now
just removes all subscriptions to the Tlm_pipe

Testing performed
Native build, sent remove all subscriptions cmd and confirmed, sent to noop multiple times and confirmed receipt

Expected behavior changes
TO remains commandable after a remove all subscriptions command

System(s) tested on

• Hardware: cFS Dev Server
• OS: Ubuntu 18.04
• Versions: Bundle main + this commit

Additional context
TO should mark empty slots with invalid MSGID, and not try to unsubscribe them - #72
TO should remove PktSize from packet add command (unused) - #73
GroundSystem add packet command definition needs update (Stream -> MsgId, should accept hex msgid, fix contents since they don't map correctly) - nasa/cFS-GroundSystem#141

Third party code
None

Contributor Info - All information REQUIRED for consideration of pull request
Jacob Hageman - NASA/GSFC

[astrogeco]

CCB 2020-12-16 APPROVED

Spawned some new issues

• Mark empty slots with invalid msgid, and don't try to unsubscribe all on them #72, TO should mark empty slots with invalid MSGID, and not try to unsubscribe them
• Remove PktSize from add packet command #73, TO should remove PktSize from packet add command (unused)
• TO add subscription command not defined correctly, doesn't accept hex MsgId cFS-GroundSystem#141, GroundSystem add packet command definition needs update (Stream -> MsgId, should accept hex msgid, fix contents since they don't map correctly)

Brings up the question: are we "fully testing" the lab apps?