Add support for Application Get Time

[mablem8]

• Add a description of Application Get Time to DOCUMENTATION.md
• Add Application Get Time to c-implementation/tab.c with an external handler
• Add a handler implementation of Application Get Time to cdh.c
• Add a handler implementation of Application Get Time to com.c
• Add an implementation of Application Get Time to python-implementation/tab.py
• Add testing of Application Get Time in python-examples/tx/tx_example.py
• Test support for Application Get Time with c-examples/cdh-monolithic and python-examples/tx

[ChadTaylor17]

• Add a description of Application Get Time to DOCUMENTATION.md
• Add Application Get Time to c-implementation/tab.c with an external handler
• Add a handler implementation of Application Get Time to cdh.c
• Add a handler implementation of Application Get Time to com.c
• Add an implementation of Application Get Time to python-implementation/tab.py
• Add testing of Application Get Time in python-examples/tx/tx_example.py
• Test support for Application Get Time with c-examples/cdh-monolithic and python-examples/tx

Periodic tests:
txcmd: app_get_time hw_id:0x1234 msg_id:0x000d src:gnd dst:cdh
reply: app_set_time hw_id:0x1234 msg_id:0x000d src:cdh dst:gnd sec:731089187 ns:184000000

txcmd: app_get_time hw_id:0x1234 msg_id:0x000e src:gnd dst:cdh
reply: app_set_time hw_id:0x1234 msg_id:0x000e src:cdh dst:gnd sec:731089188 ns:184000000

txcmd: app_get_time hw_id:0x1234 msg_id:0x000f src:gnd dst:cdh
reply: app_set_time hw_id:0x1234 msg_id:0x000f src:cdh dst:gnd sec:731089189 ns:184000000

txcmd: app_get_time hw_id:0x1234 msg_id:0x0010 src:gnd dst:cdh
reply: app_set_time hw_id:0x1234 msg_id:0x0010 src:cdh dst:gnd sec:731089190 ns:184000000

Commit: c35549e

[mablem8]

There are some issues preventing a merge of commit c35549e.

Issues with compilation

Because this commit adds external handlers for setting and getting the time in the TAB C implementation, and because these handlers have only been added to the CDH example and not the COM example, the COM example no longer compiles (i.e., a regression). When leaving a portion of the code unimplemented, be sure to add empty handlers with hard-coded success values so that the programs still compile.

Issues with attribution

Since this commit adds code written by Shize Che during the summer and fall of 2021, be sure to add his name to the contributors lists at the top of the appropriate files.

Issues with workflow

Because the proposed commit also includes a proposed fix for another issue, the proposed fix to this issue cannot be tested independently from the code aimed at the other issue. If, for example, the fix for this issue passes but the fix for the other issue fails, then the commit would be prevented from being merged despite containing a working fix.

Issues with comment formatting

When posting test results, use three ` characters to indicate the start of an output block, and use three of that same character to end the output block.

[ChadTaylor17]

Commit for app get time: 2b9fe4e