Root directory content refactoring (#1725)

* Root directory refactoring: - move info about Bootup Logo from a sepatate README to main README; - replace separate root scripts build.sh and start_dev.sh by root Makefile; - make Scripts directory and move there: flash_ts100_linux.sh script, ci/ directory, dockerfile, LICENSE_RELEASE, and PULL_REQUEST_TEMPLATE; - reconfigure build & deploy scripts according to changes

* Scripts => scripts

* Scripts -> scripts: re-add missing renamed files

* Directories refactoring: add top-level Makefile, add scripts/deploy.sh script, move github templates from top-level dir to .github, organize files inside Development Resources

* Update scripts/deploy.sh accroding to codestyle syntax shellcheck

* Makefile: add docs-deploy target for mkdocs gh-deploy

* Rename IronOS.yml > Env.yml, update related files

* Docs configs: remove empty characters

* docs/devel: update usage of new script

.github/security.md

@@ -0,0 +1,18 @@
+# Security Policy
+
+## Supported Versions
+
+Use this section to tell people about which versions of your project are
+currently being supported with security updates.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| Latest Release   | :white_check_mark: |
+| master   | :white_check_mark:                |
+
+## Reporting a Vulnerability
+
+1. Report in an issue please and tag @ralim
+2. All issues are read within 1 working week in general; often within 24 hours
+3. Issue shall recieve a comment within 14 days; but goal is < 2.
+4. Issue will be open until the vulnerability is closed in all supported versions