Implement basic app.ini and path checks to doctor cmd

[guillep2k]

This PR adds some basic app.ini and path checking to the doctor command.

In particular, it won't proceed if app.ini doesn't look healthy enough, and will provide information about the application paths the user may find useful.

Normal run

$ gitea doctor
[ 1 ] Check paths and basic configuration
- Configuration File Path:   '/home/gittest/etc/app.ini'
- Repository Root Path:      '/home/gittest/gitea-repositories'
- Data Root Path:            '/home/gittest/data'
- Custom File Root Path:     '/home/gittest/custom'
- Work directory:            '/home/gittest'
- Log Root Path:             '/home/gittest/log'
OK.

[ 2 ] Check if OpenSSH authorized_keys file id correct
OK.

Run with an empty app.ini

$ gitea --config `pwd`/empty.app.ini doctor
[ 1 ] Check paths and basic configuration
- Configuration File Path:   '/home/gittest/tmp/empty.app.ini'
- Repository Root Path:      '/home/gittest/gitea-repositories'
- Data Root Path:            '/home/gittest/tmp/data'
-     ERROR: not writable: open /home/gittest/tmp/data/doctors-order772291956: permission denied
- Custom File Root Path:     '/home/gittest/tmp/custom'
-     NOTICE: not accessible (stat /home/gittest/tmp/custom: no such file or directory)
- Work directory:            '/home/gittest/tmp'
- Log Root Path:             '/home/gittest/tmp/log'
-     ERROR: stat /home/gittest/tmp/log: no such file or directory
Error: Please check your configuration file and try again.

Run with no app.ini at all

$ gitea doctor
[ 1 ] Check paths and basic configuration
- Failed to find configuration file at '/home/gittest/tmp/custom/conf/app.ini'.
- If you've never ran Gitea yet, this is normal and '/home/gittest/tmp/custom/conf/app.ini' will be created for you.
- Otherwise check that you are running this command from the correct path and/or provide the `--config` option.
Error: Can't proceed without a configuration file

Note: I've "silenced" the default logger since its output (being asynchronous) was mixing in between the doctor's output and I find it confusing:

$ gitea doctor
[ 1 ] Check paths and basic configuration
- Configuration File Path:   '/home/gittest/etc/app.ini'
- Repository Root Path:      '/home/gittest/gitea-repositories'
2020/01/29 15:52:04 ...dules/setting/git.go:91:newGit() [I] Git Version: 2.22.0, Wire Protocol Version 2 Enabled
- Data Root Path:            '/home/gittest/data'
- Custom File Root Path:     '/home/gittest/custom'
- Work directory:            '/home/gittest'
- Log Root Path:             '/home/gittest/log'
2020/01/29 15:52:04 ...dules/setting/git.go:91:newGit() [I] Git Version: 2.22.0, Wire Protocol Version 2 Enabled
2020/01/29 15:52:04 ...dules/setting/log.go:185:generateNamedLogger() [I] Xorm Log: File(file:trace)
2020/01/29 15:52:04 ...dules/setting/log.go:185:generateNamedLogger() [I] Xorm Log: Console(console:error)
OK.

[ 2 ] Check if OpenSSH authorized_keys file id correct
OK.

I think it will be best to create a separate log for all of doctor's activities, but I leave that for another PR.

[6543]

O I had a issue once a time:
instead of ; i had a : as comment indicator -> witch result in a gitea crash without any information left where I could find the issue ...

[6543]

@guillep2k is there a chance to add : config checker?

[guillep2k]

@guillep2k is there a chance to add : config checker?

Maybe next time. I'd need to investigate all the possible valid syntaxes for app.ini lines and make a regex for that. It might not be a trivial task.

[jolheiser]

One suggestion, otherwise LGTM

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@3509a7b). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master   #10064   +/-   ##
=========================================
  Coverage          ?    42.3%           
=========================================
  Files             ?      618           
  Lines             ?    80850           
  Branches          ?        0           
=========================================
  Hits              ?    34200           
  Misses            ?    42440           
  Partials          ?     4210

Impacted Files	Coverage Δ
cmd/doctor.go	0% <ø> (ø)
modules/options/dynamic.go	68.62% <ø> (ø)

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[guillep2k]

Related: #8781 (comment)