Add feature to converter

[tadelesh]

1. support flatten
2. support custom resource, fix Support self-defined common-type resources #4861
3. fix doc multi-line issue
4. fix naming escape issue
5. fix duration default value problem

[azure-pipelines]

You may test this build by running autorest --reset and then either:

---

Add the following CLI flags

Pacakge	Flag	Description
@autorest/core	--version:http://tinyurl.com/yw64gqzb	For changes to autorest core.
@autorest/modelerfour	--use:http://tinyurl.com/yvuzzqyl	For changes to modelerfour.

Or with all

autorest --version:http://tinyurl.com/yw64gqzb --use:http://tinyurl.com/yvuzzqyl

---

or use the following in your autorest configuration:

# For changes to autorest core
version: "http://tinyurl.com/yw64gqzb"

# For changes to modelerfour
use-extension:
  "@autorest/modelerfour": "http://tinyurl.com/yvuzzqyl"

---

If this build is good for you, give this comment a thumbs up. (👍) And you should run `autorest --reset` again once you're finished testing to remove it.

[azure-pipelines]

You may test this build by running autorest --reset and then either:

---

Add the following CLI flags

Pacakge	Flag	Description
@autorest/core	--version:http://tinyurl.com/ymqy4vgd	For changes to autorest core.
@autorest/modelerfour	--use:http://tinyurl.com/ymcaeo2t	For changes to modelerfour.

Or with all

autorest --version:http://tinyurl.com/ymqy4vgd --use:http://tinyurl.com/ymcaeo2t

---

or use the following in your autorest configuration:

# For changes to autorest core
version: "http://tinyurl.com/ymqy4vgd"

# For changes to modelerfour
use-extension:
  "@autorest/modelerfour": "http://tinyurl.com/ymcaeo2t"

---

If this build is good for you, give this comment a thumbs up. (👍) And you should run `autorest --reset` again once you're finished testing to remove it.

[azure-pipelines]

You may test this build by running autorest --reset and then either:

---

Add the following CLI flags

Pacakge	Flag	Description
@autorest/core	--version:http://tinyurl.com/yruf98l3	For changes to autorest core.
@autorest/modelerfour	--use:http://tinyurl.com/yt5kcusl	For changes to modelerfour.

Or with all

autorest --version:http://tinyurl.com/yruf98l3 --use:http://tinyurl.com/yt5kcusl

---

or use the following in your autorest configuration:

# For changes to autorest core
version: "http://tinyurl.com/yruf98l3"

# For changes to modelerfour
use-extension:
  "@autorest/modelerfour": "http://tinyurl.com/yt5kcusl"

---

If this build is good for you, give this comment a thumbs up. (👍) And you should run `autorest --reset` again once you're finished testing to remove it.

[azure-pipelines]

You may test this build by running autorest --reset and then either:

---

Add the following CLI flags

Pacakge	Flag	Description
@autorest/core	--version:http://tinyurl.com/yrutqw3u	For changes to autorest core.
@autorest/modelerfour	--use:http://tinyurl.com/2xb7vtek	For changes to modelerfour.

Or with all

autorest --version:http://tinyurl.com/yrutqw3u --use:http://tinyurl.com/2xb7vtek

---

or use the following in your autorest configuration:

# For changes to autorest core
version: "http://tinyurl.com/yrutqw3u"

# For changes to modelerfour
use-extension:
  "@autorest/modelerfour": "http://tinyurl.com/2xb7vtek"

---

If this build is good for you, give this comment a thumbs up. (👍) And you should run `autorest --reset` again once you're finished testing to remove it.

[azure-pipelines]

You may test this build by running autorest --reset and then either:

---

Add the following CLI flags

Pacakge	Flag	Description
@autorest/core	--version:http://tinyurl.com/ysmvvny9	For changes to autorest core.
@autorest/modelerfour	--use:http://tinyurl.com/ynyodql5	For changes to modelerfour.

Or with all

autorest --version:http://tinyurl.com/ysmvvny9 --use:http://tinyurl.com/ynyodql5

---

or use the following in your autorest configuration:

# For changes to autorest core
version: "http://tinyurl.com/ysmvvny9"

# For changes to modelerfour
use-extension:
  "@autorest/modelerfour": "http://tinyurl.com/ynyodql5"

---

If this build is good for you, give this comment a thumbs up. (👍) And you should run `autorest --reset` again once you're finished testing to remove it.