Add macOS support

[deg0nz]

I added the support for macOS for ProxyMan. I created this PR so we can discuss some stuff about the implementation.

For now, the following things are implemented:

• Determining operation system and sourceing corresponding OS-related file to have the right functions for each OS in place
• Change system-wide settings in macOS (networksetup as mentioned in #11 )
  • On macOS, proxy settings are set per network device. So I added a second selection prompt to determine for which network devices proxies should be set.
  • Network devices are automatically discovered and shown to the user
• Terminal's settings work as before, but some adjustments were needed to work on macOS
• Configurations for npm/yarn and git are untouched since they are identical to Linux
• non-macOS related configurations (like KDE, apt, docker, ...) are ignored in the macOS-part

What's missing:

• Printing networksetup proxy configurations. To make this pretty, there is need for some data aggregation to be made, since networksetup is a bit chatty about that. A simple print for all network devices would be too much. So I left that part out for now.
• I think setting variables other than the ones for the Terminal environment (as mentioned in #12) is not necessary, because the configurations via networksetup are system-wide
• I would like to add auto-discovery for proxies additionally to setting the proxies manually per-device since macOS supports this function later
• In my experience you only want to change proxy settings for some devices on macOS (most of the time). It could make sense to add the configuration of the affected devices into the profiles that can already be saved by ProxyMan

To be done/discussed before merging:

• [x] I'm not so happy with the file names of the splitted functions for macOS and Linux (respectively main_macos.sh and main_linux.sh) because they can cause confusion by the user (one could think that those are the main.sh to be executed for the corresponding OS). I will change this to something that makes more sense for this scenario.
• [x] networksetup throws an error when setting proxy settings with user credentials: networksetup[71185:16035891] error -25299 attempting to create account and password for proxy, but credentials actually get updated in the system and work. Maybe this is a keychain-issue... But I think we can ignore that for the first version.
• [x] This branch should be testet on Linux to ensure that everything still works as expected

[deg0nz]

I tried the macOS version on another machine today. Turns out, that realpath (readlink -f equivalent for BSD) does not come with macOS per default. It seems that I had installed coreutils a long time ago (and forgot about it), so it worked out of the box on my machine. I added a shell-only substitute that I found on here on GitHub.

[himanshub16]

Thanks a lot @deg0nz Your contribution is really helpful and adds a lot of value by providing support on MacOS.

I'm sorry for not responding. There has been some delay from my end as I had been occupied. Will definitely have a look at this later this week/during weekend.

[deg0nz]

No problem, take your time :) I'm currently using my fork at work and found some quirks here and there. I need to do some more testing with the networksetup part. So no need to rush :)

[deg0nz]

Okay, I fixed the problem with the networksetup part and everything seems to work on macOS as far as I tested it. I also tested the changes on a Linux machine (My LinuxMint VM) and everything works as expected.

From my perspective, this is ready to merge now. Any tests and suggestions for improvements are appreciated, of course :)

[FatehAK]

Has this feature been merged? Does proxyman support macos now?

[deg0nz]

@FatehAK Unfortunately it is not merged yet, but you can just use my fork by using the macOS branch until it gets merged.

I'm using this for almost a year now and it seems to be working fine. I would also be happy if someone else could test this :)

[FatehAK]

It works perfectly @deg0nz. I've used it for the past few days haven't faced any issues.

[deg0nz]

Just FYI:

Me and my colleagues are using this for almost 2 years now without any problems. I think it can be considered stable