add support for --tls flag (#146)

[r-mol]

What was changed

1. cli/app.go -> Added --tls flag to app.flags slice
2. cli/factory.go -> Added parsing --tls flag with checking on error. And added the logic that when the flag is activated, the host is taken from the address/localhost
3. cli/flags.go -> Added const of --tls flag name
4. cli_curr/app.go -> Added --tls flag to app.flags slice
5. cli_curr/factory.go -> Added parsing --tls flag with checking on error. And added the logic that when the flag is activated, the host is taken from the address/localhost

Why?

I am connecting to my server over a TLS connection and I had to duplicate my host from the --address flag to the --tls_server_name flag. This cluttered up the command, as well as misleading.

Checklist

1. Closes #146

2. How was this tested:

• By internal tests, but with adding this flag
• By connecting to local server with this flag

5. Any docs updates needed? - NO

Related to same issue

https://github.com/temporalio/cli/pull/210

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[r-mol]

Hi! It's been a while since my request was approved for the merge, but I haven't heard any updates yet on when it will be merged. Is there anything else that needs to be done on my end, or something else that is slowing down the merge process? Let me know if there's anything I can do to help. Thanks!