UX: Tags/branches awareness

[screamerbg]

This PR fixes/adds:

• Tags handling in Mercurial/hg
• Tags/releases awareness across various mbed CLI commands.
• The Git.outgoing() routine will now correctly check if a local branch exists. Previously mbed CLI was throwing an error when trying to check outgoing changes by comparing remote master branch and non-existent local master branch

Details/Logs

Mercurial tags are now correctly displayed

/tmp/hg-test]$ mbed ls
hg-test (#38124d242060)
`- mbed-os (#dc6cb4f1a87a, tag: tip)
   |- core (#2f7f0a7fc6b3)
   |  |- mbed-rtos (#bdd541595fc5)
   |  |- mbed-uvisor (#af27c87db9c2)
   |  `- mbedtls (#dee5972f341f)
   |- hal (#f1c94b98286f)
   |  `- targets/TARGET_Freescale (#a35ebe05b3bd)
   |     |- TARGET_KPSDK_MCUS (#e4d670b91a9a, tag: tip)
   |     `- TARGET_MCU_K64F (#c5e2f793b59a, tag: tip)
   |- net (#1ff180f69e71, tag: tip)
   |  |- ESP8266Interface (#c0808849cb89, tag: tip)
   |  |  `- ESP8266 (#c18644e0e0dd)
   |  |     `- ATParser (#6b8190f55d83)
   |  |        `- BufferedSerial (#a0d37088b405, tag: tip)
   |  |           `- Buffer (#89564915f2a7, tag: tip)
   |  |- LWIPInterface (#1efb0d91c223)
   |  |  |- lwip (#08f08bfc3f3d, tag: tip)
   |  |  |- lwip-eth (#4380f0749039)
   |  |  `- lwip-sys (#12e78a2462d0)
   |  |- NetworkSocketAPI (#6cfd38609828)
   |  |  `- DnsQuery (#18a6b52be896)
   |  |- mbed-client (#e36098b177a4, tag: tip)
   |  |- mbed-client-c (#5d91b0f5038c, tag: tip)
   |  |- mbed-client-classic (#723bfe4dd180, tag: tip)
   |  |- mbed-client-mbedtls (#80a66815c791, tag: tip)
   |  |- mbed-trace (#506ad37c6bd7, tag: tip)
   |  `- nanostack-libservice (#a87c5afee2a6, tag: tip)
   `- tools (#ca00ce2bd4be)

Also mbed update and other commands will now show revision hashes and associated tags/releases (if any).

/tmp/mbed-os-example-client:$ mbed update mbed-os-5.6.1
[mbed] Updating program "mbed-os-example-client" to branch/tag "mbed-os-5.6.1"
[mbed] Updating library "easy-connect" to rev #bf821b0695cc
[mbed] Removing library "easy-connect/wifi-x-nucleo-idw01m1" (obsolete)
[mbed] Updating library "easy-connect/atmel-rf-driver" to rev #3cc6010188c0
[mbed] Updating library "easy-connect/esp8266-driver" to rev #fdb44a4bedbb
[mbed] Adding library "easy-connect/esp8266-driver/ESP8266/ATParser" from "https://github.com/ARMmbed/ATParser" at rev #a2cb09990f11
[mbed] Updating library "easy-connect/mcr20a-rf-driver" to rev #9aac10474702
[mbed] Updating library "easy-connect/stm-spirit1-rf-driver" to rev #bee61bbe6807
[mbed] Updating library "mbed-client" to rev #31e5ce203cc0 (tag: v3.0.0)
[mbed] Updating library "mbed-client/mbed-client-c" to rev #ecfa619e42b2 (tag: v6.0.0)
[mbed] Updating library "mbed-client/mbed-client-classic" to rev #4e66929607c3
[mbed] Updating library "mbed-client/mbed-client-mbed-tls" to rev #7e1b6d815038 (tags: mbedCloudClient-R1.1, mbedCloudClient-R1.1-RC1)
[mbed] Updating library "mbed-os" to rev #cc7556a92fb9 (tags: mbed-os-5.6.1, mbed_lib_rev152)
[mbed] Updating library "pal" to rev #60ce64d5ec35

[sg-]

LGTM 👍

[theotherjimmy]

Looks fine. I would complain about some lines being extra long, but I don't think you caused that and it seems consistent with the rest of the code.

[screamerbg]

@theotherjimmy Yes, I agree that some are a bit too long, especially the ones formatting the output. I'd like to look at improving these in the future.