Allow to override clickhouse_repo, add to use alternative apt key

Now it's possible to define own clickhouse_repo variable to
prove apt source line to use.

Now it's possible to define own key id and keyserver to download
the apt key, or to provide the apt key within a variable
`clickhouse_repo_key_data`.

Closes: AlexeySetevoi#15

README.md

@@ -138,6 +138,37 @@ F: Flag for remove clickhouse from host(disabled by default)
 clickhouse_remove: no
 ```
 
+Private mirror
+--------------
+To use a private mirror you need to provide your own repository string and
+the key. Key may be provided as key name to download from a keyserver or
+as armored GPG public key (the key itself). To use a key from a keyring,
+`clickhouse_repo_key` and `clickhouse_repo_keyserver` should be provided.
+
+To use a key in verbatim form, `clickhouse_repo_key_data` should be provided.
+
+Custom mirror may be provided with `clickhouse_repo` variable.
+
+Examples:
+```
+clickhouse_repo: 'deb http://apt.example.com/aptly/clickhouse xenial main'
+clickhouse_repo_key: AABBCCDD
+clickhouse_repo_keyserver: keyserver.example.com
+```
+or
+```
+clickhouse_repo: 'deb http://apt.example.com/aptly/clickhouse xenial main'
+clickhouse_repo_key_data: |
+    -----BEGIN PGP PUBLIC KEY BLOCK-----
+    Version: GnuPG v1.4.12 (GNU/Linux)
+    mQANBFGspxsACADWgH5qqQtEa+Bjqd33X0PiRNcUf/Vt9m828uUuF5uRCEKruUG0
+    (few lines skipped)
+    LU/GfPzkCXlOt3Ud4L2EdvgQp/38VCNKmWi568soZnTwpjUt9AuN7iK3fm4=
+    =4dWC
+    -----END PGP PUBLIC KEY BLOCK-----
+```
+
+
 Example Playbook
 ----------------
 

defaults/main.yml

@@ -1,6 +1,21 @@
 ---
 # defaults file for clickhouse
 
+# Settings for apt repo
+clickhouse_repo: "deb http://repo.yandex.ru/clickhouse/deb/stable/ main/"
+clickhouse_repo_old: "deb http://repo.yandex.ru/clickhouse/xenial stable main"
+clickhouse_repo_keyserver: keyserver.ubuntu.com
+clickhouse_repo_key: E0C56BD4
+clickhouse_package:
+  - clickhouse-client
+  - clickhouse-server-base
+  - clickhouse-server-common
+clickhouse_path_configdir: "/etc/clickhouse-server"
+clickhouse_path_logdir: "/var/log/clickhouse-server"
+clickhouse_path_data: "/var/lib/clickhouse/"
+clickhouse_path_tmp: "/var/lib/clickhouse/tmp/"
+
+
 #Flag for using with requirements check
 clickhouse_supported: no
 #Type of installation (package,source)

vars/Ubuntu_precise.yml

@@ -1,14 +1,2 @@
+---
 clickhouse_supported: yes
-clickhouse_repo: "deb http://repo.yandex.ru/clickhouse/deb/stable/ main/"
-clickhouse_repo_old: "deb http://repo.yandex.ru/clickhouse/xenial stable main"
-clickhouse_repo_keyserver: keyserver.ubuntu.com
-clickhouse_repo_key: E0C56BD4
-clickhouse_package:
-  - clickhouse-client
-  - clickhouse-server-base
-  - clickhouse-server-common
-clickhouse_path_configdir: "/etc/clickhouse-server"
-clickhouse_path_logdir: "/var/log/clickhouse-server"
-clickhouse_path_data: "/var/lib/clickhouse/"
-clickhouse_path_tmp: "/var/lib/clickhouse/tmp/"
-

vars/Ubuntu_trusty.yml

@@ -1,13 +1,2 @@
+---
 clickhouse_supported: yes
-clickhouse_repo: "deb http://repo.yandex.ru/clickhouse/deb/stable/ main/"
-clickhouse_repo_old: "deb http://repo.yandex.ru/clickhouse/xenial stable main"
-clickhouse_repo_keyserver: keyserver.ubuntu.com
-clickhouse_repo_key: E0C56BD4
-clickhouse_package:
-  - clickhouse-client
-  - clickhouse-server-base
-  - clickhouse-server-common
-clickhouse_path_configdir: "/etc/clickhouse-server"
-clickhouse_path_logdir: "/var/log/clickhouse-server"
-clickhouse_path_data: "/var/lib/clickhouse/"
-clickhouse_path_tmp: "/var/lib/clickhouse/tmp/"

vars/Ubuntu_xenial.yml

@@ -1,13 +1,2 @@
+---
 clickhouse_supported: yes
-clickhouse_repo: "deb http://repo.yandex.ru/clickhouse/deb/stable/ main/"
-clickhouse_repo_old: "deb http://repo.yandex.ru/clickhouse/xenial stable main"
-clickhouse_repo_keyserver: keyserver.ubuntu.com
-clickhouse_repo_key: E0C56BD4
-clickhouse_package:
-  - clickhouse-client
-  - clickhouse-server-base
-  - clickhouse-server-common
-clickhouse_path_configdir: "/etc/clickhouse-server"
-clickhouse_path_logdir: "/var/log/clickhouse-server"
-clickhouse_path_data: "/var/lib/clickhouse/"
-clickhouse_path_tmp: "/var/lib/clickhouse/tmp/"