`manage.safe_accept` has several significant bugs

Description of Issue

(1) Failure to pass __opts__ to the ssh client

Overrides passed on the command line are ignored.

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L565

(2) Hard-coded assumption about len(16) fingerprints

Most fingerprints appear to be len(32) in recent salt releases.

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L571

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L34

(3) Fingerprints returned from key.finger are actually located at ret[minion_id]['return']

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L570

(4) Attempt to delete from a dictionary while iterating over it

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L578

(5) Implicit assumption that the minion names in the roster are meaningful

This is a bad assumption in bootstrapping scenarios where all the caller has is an IP address and, thus, the roster can't "know" the minion name in advance of ssh-ing in.

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L574

(6) Failure to pass __opts__ when adding the keys

https://github.com/saltstack/salt/blob/c65fcc5a9260a5d8196d79554618b748ca0623fa/salt/runners/manage.py#L588

(7) Failure to check that the current master key matches the master key cached by the minions, if any

Might as well catch a possible minion-side authentication failure while we're at it.

Setup

Steps to Reproduce Issue

salt-run -c <some_other_config> manage.safe_accept <some_minion>

Versions Report

           Salt: 2019.2.1
 
Dependency Versions:
           cffi: Not Installed
       cherrypy: Not Installed
       dateutil: 2.8.0
      docker-py: Not Installed
          gitdb: Not Installed
      gitpython: Not Installed
          ioflo: Not Installed
         Jinja2: 2.10.1
        libgit2: Not Installed
        libnacl: Not Installed
       M2Crypto: Not Installed
           Mako: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.6.2
   mysql-python: Not Installed
      pycparser: Not Installed
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: Not Installed
         Python: 3.6.8 (default, Aug 20 2019, 17:12:48)
   python-gnupg: Not Installed
         PyYAML: 3.13
          PyZMQ: 18.1.0
           RAET: Not Installed
          smmap: Not Installed
        timelib: Not Installed
        Tornado: 4.5.3
            ZMQ: 4.3.2
 
System Versions:
           dist: Ubuntu 18.04 bionic
         locale: UTF-8
        machine: x86_64
        release: 4.15.0-64-generic
         system: Linux
        version: Ubuntu 18.04 bionic

Start by reading salt/runners/manage.py around the linked lines 34 and 565-588, then reproduce the behavior with salt-run -c <some_other_config> manage.safe_accept <some_minion>. Done means the command handles the listed option propagation, fingerprint structure and length, roster naming, dictionary iteration, key addition, and master-key checks correctly.