(DOCSP-35641) Remove mentions of CentOS. (#222)

[JIRA](https://jira.mongodb.org/browse/DOCSP-35641)
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Author: lmkerbey-mdb

source/core/requirements.txt

@@ -418,7 +418,7 @@ Intel/AMD (``x86_64``) Hardware Architectures
      - 10, 11
      - 11, 12
 
-   * - Red Hat Enterprise Linux / CentOS
+   * - Red Hat Enterprise Linux
      - 7, 8, 9
      - 7 *(deprecated)*, 8, 9
 

source/includes/list-tables/v7-agent-platform-support-table.rst

@@ -12,7 +12,7 @@
       - 4.0
       - 3.6
     * - x86_64
-      - RHEL/CentOS/Oracle Linux 7
+      - RHEL/Oracle Linux 7
       - :icon:`check-circle`
       - :icon:`check-circle`
       - :icon:`check-circle`
@@ -165,7 +165,7 @@
       - :icon:`check-circle`
       - :icon:`check-circle`
     * - ARM
-      - RHEL/CentOS 8
+      - RHEL 8
       - :icon:`check-circle`
       - :icon:`check-circle`
       - :icon:`check-circle`
@@ -174,7 +174,7 @@
       -
       -
     * -
-      - RHEL/CentOS 9
+      - RHEL 9
       - :icon:`check-circle`
       - :icon:`check-circle`
       -
@@ -219,7 +219,7 @@
       -
       -
     * - PowerPC/ ppc64le
-      - RHEL/ Centos 7
+      - RHEL 7
       - :icon:`check-circle`
       - :icon:`check-circle`
       - :icon:`check-circle`
@@ -228,7 +228,7 @@
       - :icon:`check-circle`
       - :icon:`check-circle`
     * - 
-      - RHEL/ CentOS 8
+      - RHEL 8
       - :icon:`check-circle`
       - :icon:`check-circle`
       - :icon:`check-circle`

source/includes/rhel-ulimit-conf-file.rst

@@ -1,4 +1,4 @@
-:abbr:`RHEL (Red Hat Enterprise Linux)` and CentOS 6 limit the maximum
+:abbr:`RHEL (Red Hat Enterprise Linux)` limits the maximum
 number of user processes to ``1024``. This overrides the general
 user process limit (``ulimit -u``) setting.