Migrate the contents of TLS.md into README.md (valkey-io#927)

Migrate the contents in TLS.md into TLS sections including building,
running and detail supports. TODO list in the TLS.md is almost done
except the implementation of benchmark support is still not the best
approach which should migrate to hiredis async mode.

Closes valkey-io#888

---------

Signed-off-by: I Hsin Cheng <[email protected]>
Signed-off-by: Viktor Söderqvist <[email protected]>
Co-authored-by: Viktor Söderqvist <[email protected]>

README.md

@@ -25,10 +25,18 @@ It is as simple as:
     % make
 
 To build with TLS support, you'll need OpenSSL development libraries (e.g.
-libssl-dev on Debian/Ubuntu) and run:
+libssl-dev on Debian/Ubuntu).
+
+To build TLS support as Valkey built-in:
 
     % make BUILD_TLS=yes
 
+TO build TLS as Valkey module:
+
+    % make BUILD_TLS=module
+
+Note that sentinel mode does not support TLS module.
+
 To build with experimental RDMA support you'll need RDMA development libraries
 (e.g. librdmacm-dev and libibverbs-dev on Debian/Ubuntu). For now, Valkey only
 supports RDMA as connection module mode. Run:
@@ -156,8 +164,41 @@ line, with exactly the same name.
 Running Valkey with TLS:
 ------------------
 
-Please consult the [TLS.md](TLS.md) file for more information on
-how to use Valkey with TLS.
+### Running manually
+To manually run a Valkey server with TLS mode (assuming `./gen-test-certs.sh` was invoked so sample certificates/keys are available):
+
+* TLS built-in mode:
+    ```
+    ./src/valkey-server --tls-port 6379 --port 0 \
+        --tls-cert-file ./tests/tls/valkey.crt \
+        --tls-key-file ./tests/tls/valkey.key \
+        --tls-ca-cert-file ./tests/tls/ca.crt
+    ```
+
+* TLS module mode:
+    ```
+    ./src/valkey-server --tls-port 6379 --port 0 \
+        --tls-cert-file ./tests/tls/valkey.crt \
+        --tls-key-file ./tests/tls/valkey.key \
+        --tls-ca-cert-file ./tests/tls/ca.crt \
+        --loadmodule src/valkey-tls.so
+    ```
+
+Note that you can disable TCP by specifying `--port 0` explicitly.
+It's also possible to have both TCP and TLS available at the same time,
+but you'll have to assign different ports.
+
+Use `valkey-cli` to connect to the Valkey server:
+```
+./src/valkey-cli --tls \
+    --cert ./tests/tls/valkey.crt \
+    --key ./tests/tls/valkey.key \
+    --cacert ./tests/tls/ca.crt
+```
+
+Specifying `--tls-replication yes` makes a replica connect to the primary.
+
+Using `--tls-cluster yes` makes Valkey Cluster use TLS across nodes.
 
 Running Valkey with RDMA:
 ------------------