docs: port diagrams to PlantUML

[demianova]

Fix #1363

[mystamps-bot]

	1 Message
📖	@demianova thank you for the PR! All quality checks have been passed! Next step is to wait when @php-coder will review this code

Generated by 🚫 Danger

[php-coder]

Excellent! 🥇

[php-coder]

Travis failed with unrelated errors:

1. rflint fails because one of its dependency:

=====> Run robot framework lint

Traceback (most recent call last):
  File "/home/travis/.local/bin/rflint", line 5, in <module>
    from rflint.__main__ import main
  File "/home/travis/.local/lib/python2.7/site-packages/rflint/__init__.py", line 1, in <module>
    from .rflint import RfLint, ERROR, WARNING
  File "/home/travis/.local/lib/python2.7/site-packages/rflint/rflint.py", line 30, in <module>
    from .parser import RobotFactory, SuiteFile, ResourceFile
  File "/home/travis/.local/lib/python2.7/site-packages/rflint/parser/__init__.py", line 1, in <module>
    from .parser import (SuiteFolder, ResourceFile, SuiteFile, RobotFactory, 
  File "/home/travis/.local/lib/python2.7/site-packages/rflint/parser/parser.py", line 24, in <module>
    from robot.parsing.txtreader import TxtReader
ImportError: No module named txtreader

2. Danger doesn't like push with force:

=====> Run danger

fatal: couldn't find remote ref refs/heads/convert_diagrams
fatal: couldn't find remote ref refs/heads/convert_diagrams
fatal: couldn't find remote ref refs/heads/convert_diagrams
fatal: couldn't find remote ref refs/heads/convert_diagrams
From https://github.com/php-coder/mystamps
 * [new tag]           0.1        -> 0.1
 * [new tag]           0.1.1      -> 0.1.1
 * [new tag]           0.1.2      -> 0.1.2
 * [new tag]           0.1.3      -> 0.1.3
 * [new tag]           0.2        -> 0.2
 * [new tag]           0.3        -> 0.3
 * [new tag]           0.4        -> 0.4
 * [new tag]           0.4.1      -> 0.4.1
 * [new tag]           0.4.2      -> 0.4.2
/home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/scm_source/git_repo.rb:117:in `raise_if_we_cannot_find_the_commit': Commit 27ff1b8d doesn't exist. Are you running `danger local/pr` against the correct repository? Also this usually happens when you rebase/reset and force-pushed. (RuntimeError)
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/scm_source/git_repo.rb:99:in `ensure_commitish_exists_on_branch!'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/request_sources/github/github.rb:112:in `setup_danger_branches'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/danger_core/environment_manager.rb:58:in `ensure_danger_branches_are_setup'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/danger_core/dangerfile.rb:269:in `setup_for_running'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/danger_core/dangerfile.rb:280:in `run'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/danger_core/executor.rb:29:in `run'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/lib/danger/commands/runner.rb:73:in `run'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/claide-1.0.3/lib/claide/command.rb:334:in `run'
	from /home/travis/.rvm/gems/ruby-2.5.3/gems/danger-7.0.1/bin/danger:5:in `<top (required)>'
	from /home/travis/.rvm/gems/ruby-2.5.3/bin/danger:23:in `load'
	from /home/travis/.rvm/gems/ruby-2.5.3/bin/danger:23:in `<main>'
	from /home/travis/.rvm/gems/ruby-2.5.3/bin/ruby_executable_hooks:24:in `eval'
	from /home/travis/.rvm/gems/ruby-2.5.3/bin/ruby_executable_hooks:24:in `<main>'